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Australia’s Electronics Magazine SILICON CHIP JULY 2001 6 $ 60* INC GST ISSN 1030-2662 07 NZ $ 7 50 INC GST PRINT POST APPROVED - PP255003/01272 9 771030 266001 siliconchip.com.au PROJECTS TO BUILD - SERVICING - COMPUTERS - VINTAGE RADIO - AUTO ELECTRONICS HEARTMATE HEART RATE MONITOR TO BUILD “Do Not Disturb” AUTOMATIC ’PHONE HANGUPERER FEATURE: PIC-TOC DIGITA L AMPLI HIFI FIERS The World’s Simplest Clock July 2001  1 AND EVEN MORE PROJECTS INSIDE! RT SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.prismsound.com Contents Vol.14, No.7; July 2001 FEATURES   6  Digital Amplifiers Are Here! The writing is on the wall for analog audio amplifiers. A new breed of digital audio power amplifiers is about to take over and they offer lots of benefits – by Jim Rowe 81  Review: Tektronix TDS3014 Colour Oscilloscope It fits in a shoebox yet boasts an impressive range of features including a colour LCD, an inbuilt disk drive and a printer port – by Leo Simpson 86  Review: PrimSound dScope Audio Test System New Windows-based audio test system measures in both the analog and digital domains – by Leo Simpson The HeartMate Heart Rate Monitor – Page 28. PROJECTS TO BUILD 28  The HeartMate Heart Rate Monitor Build it and keep tabs on your ticker. It’s just the shot for monitoring your heart rate during exercise, so you don’t overdo it – by John Clarke 43  Do Not Disturb Telephone Timer It takes your phone off-hook and automatically hangs up again after a preset time. A LED indicates when the phone is off-hook – by John Clarke 60  Pic-Toc – A Simple Digital Alarm Clock What has less than 20 parts and can wake you in the morning? It’s the PicToc alarm clock and it’s really easy to build – by Michael Moore 66  A Fast Universal Battery Charger; Pt.2 Second article has all the construction details. This unit will solve all your charging problems once and for all – by John Clarke COMPUTERS Do Not Disturb Telephone Timer – Page 43. 14  A PC To Die For, Pt.2 – You Can Build It For Yourself Partitioning & formatting the hard disk drive, installing the operating system & squashing the bugs – by Greg Swain 77  Computer Tips: Backing Up Your Email Backing up your email, DOS for Windows Me, HyperTerminal update & making a quick exit from Windows 98 – by Peter Smith SPECIAL COLUMNS 38  Serviceman’s Log The Televideo that committed hari-kari – by the TV Serviceman 90  Vintage Radio How to repair Bakelite cabinets – by Rodney Champness DEPARTMENTS   2  Publisher’s Letter   98  Ask Silicon Chip 57  Subscriptions Form 100  Notes & Errata 58 Mailbag 102 Market Centre 88  Products Showcase 104  Advertising Index Pic Toc: A Simple Digital Alarm Clock – Page 60. Penguin’s off! Unfortunately, lack of space has forced us to hold over the third article on “Using Linux As An Internet Gateway”. It’ll be there next month – we promise! July 2001  1 PUBLISHER’S LETTER www.siliconchip.com.au Publisher & Editor-in-Chief Leo Simpson, B.Bus., FAICD Production Manager Greg Swain, B.Sc.(Hons.) Technical Staff John Clarke, B.E.(Elec.) Peter Smith Ross Tester Rick Walters Reader Services Ann Jenkinson Advertising Enquiries David Polkinghorne Phone (02) 9979 5644 Fax (02) 9979 6503 Regular Contributors Brendan Akhurst Rodney Champness Julian Edgar, Dip.T.(Sec.), B.Ed Jim Rowe, B.A., B.Sc, VK2ZLO Mike Sheriff, B.Sc, VK2YFK Philip Watson, MIREE, VK2ZPW Bob Young SILICON CHIP is published 12 times a year by Silicon Chip Publications Pty Ltd. ACN 003 205 490. ABN 49 003 205 490 All material copyright ©. No part of this publication may be reproduced without the written consent of the publisher. Printing: Hannanprint, Dubbo, NSW. Distribution: Network Distribution Company. Subscription rates: $69.50 per year in Australia. For overseas rates, see the subscription page in this issue. Editorial & advertising offices: Unit 8, 101 Darley St, Mona Vale, NSW 2103. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 9979 5644. Fax (02) 9979 6503. E-mail: silchip<at>siliconchip.com.au ISSN 1030-2662 * Recommended and maximum price only. 2  Silicon Chip The Electric Wiring Debate – have YOU sent in your “Statement of Will”!? The electrical wiring debate goes on. But while most people agree with the campaign, the number who have responded positively by sending in their signed “Statement of Will” or copy of their “MY WILL” letter to their parliamentarians has been pretty underwhelming. Have YOU sent yours in? In effect, we have plenty of “Noddies” but most seem unable to pick up a pen. I suppose this fits in with the general picture of Australians being apathetic but this is an issue which affects us all – all people who want to be able to work on electrical equipment. The campaign is really two-pronged. We’re not just campaigning that people should be allowed to do their own home-wiring. There also should be no restrictions on people working on mains-powered equipment. Let’s get right down to the grass roots. For example, this issue also involves anyone who wants to work on vintage radios – they are mains-powered aren’t they! Not only in Queensland, but now in most other states, you can’t legally work on your own vintage radios. Happy with that? And amateur operators? Sorry, you can’t touch a mains-powered transceiver. In fact, we’re talking about anyone who wants to assemble or service mains-powered equipment, whether it is a DIY project described in SILICON CHIP, servicemen working on TVs, VCRs, microwave ovens, photocopiers and printers, PCs and their monitors, and so on. Yes, if you’re a tech, this law stops YOU earning a living! It also embraces people working in the broadcast industry working on studio equipment and transmitters, technicians servicing medical equipment in hospitals and doctors’ surgeries and so on. Even if you have a PhD in electrical engineering, your career is over. Presently in Queensland, all these people are working illegally if they connect or disconnect non-live mains-voltage wiring and do not at least have a restricted licence. And even if they have a restricted licence, they can not legally construct or modify mains-voltage sections of any electronic equipment, nor troubleshoot such sections when they are live. That such a situation could exist and spread to other states is utterly ludicrous. Now don’t be apathetic. You will be stopped from doing what you presently do now, which is to work on all forms of mains-powered equipment. Maybe you don’t care if you are never legally allowed to do your own home wiring. But you WILL CARE if you are eventually stopped from building a kit because it’s got a mains powered transformer and/or other mains-voltage circuitry. This is the situation in Queensland RIGHT NOW. If we don’t do anything, it WILL become the same right across Australia. Actually, if you take the present law in Queensland, it probably means that no-one can even open up their own computer to change a card or insert more memory. After all, most PCs are mains-powered. Furthermore, as outlined elsewhere in this issue, no electrical or electronics engineer, no matter how highly qualified or experienced, can ever get a licence to do wiring. If he lives in NSW, and if he is a power, protection or control engineer, he has a slight chance of being able to get one, but only after he has been approved so he can do the prescribed TAFE course. So we have the situation where engineers can design large and complex electrical installations but they can never touch the wiring. They can’t even work on the ordinary domestic fixed wiring system in their own homes! Now come on – let’s get REAL. As part of getting REAL, let us acknowledge that at the very least, home-owners should be legally able to replace defective light switches and power points and install light fittings. They should also be able to temporarily unscrew light switches and power points from walls and tape them up, so that they won’t be painted over during re-decorating. After all, that is what a lot of people do now and surely no one can argue that this is a significant source of fatalities – it clearly isn’t. But we are going even further. We are campaigning so that home-owners can legally do any domestic wiring right up to the switch-board, just as they do in New Zealand and most other western countries. In fact, in New Zealand home-owners can design and construct their own switchboard. They can also bolt it up and connect the house wiring to it under the supervision of an electrician! Concurrently, we are campaigning to have all the silly restrictions on people working on all mains-powered equipment removed. OK, so how have electricians reacted to this campaign? On the whole, they have been utterly negative. They generally refuse to accept the fact that most western countries: (a) permit home-owners to do mains wiring and appliance repairs; and (b) have a better safety record than Australia’s. While denying these facts they go on to claim that conditions in Australia are somehow more dangerous than elsewhere. On this last claim, the electricians MAY have a point! Not that our 240VAC electrical system is inherently any more dangerous than in most other countries. That is patently untrue. Some electricians have even tried to convince me that because we have so many migrants in this country, the situation is more dangerous because migrants don’t know or care about regulations and safety and just wire things up willy-nilly. Well, that is nonsense. Migrants are no more careless and/or lacking in the relevant knowledge about wiring standards than other Australians. No, the reasons why the situation in Australia may be more dangerous are twofold. First, inspections of domestic wiring by the electrical authorities are now practically non-existent or cursory at best. Electricians generally feel that this is wrong and that it lets the “cowboys” get away with bad and unsafe practices. That’s fair comment. Of course, as far as letting home-owners do their own wiring, we are advocating that thorough inspection be mandatory for new installations and extensions. We have done that from the outset. Second, there is no information available to the public on how domestic electrical wiring should be done. You can go into a hardware store and buy the cable, the conduit, the junction boxes and other fittings but nowhere does it tell you what cable should be used, how it should be wired and so on. This is a “chicken and egg” situation. Because it is illegal, no information on how to do domestic wiring is available. Well, as soon as it becomes legal, the information on how to do it will become available. In countries where it is legal for home-owners to do their own wiring, information on how to do it is freely available. For instance, the New Zealand government sells “code of practice” booklets to home-owners there (NZ$5 each), to provide guidance on various aspects of electrical wiring and appliance repairs. So while ever it is illegal in Australia for home-owners to do their own domestic wiring, the information on how to do it is likely to be unavailable. Unless we change that, we will always have the potentially dangerous situation whereby home-owners CAN LEGALLY BUY all the electrical cable and fittings they want but never be properly informed on how it should be used. Properly informing the public ensures that wiring done by home-owners will become safer. Add in the requirement for inspections, as in New Zealand, and the overall safety of wiring in homes must become much safer than it is now. After all, hundreds of thousands of Australians have illegally done their own “electrical work”, and they will continue to illegally do it if the system does not change. So let’s replace the electrician instigated official “voodoo” with some REAL PUBLIC KNOWLEDGE and just make the domestic electrical environment much safer, as most other western countries have done! Electricians can’t have it all their own way. If they are really concerned about safety, then they should be in favour of the changes we advocate. That way everyone would be much better informed about how safe wiring must be done. Actually, we don’t think that electricians are all that concerned about safety. If they were, the electricians who control the state Licensing Boards, Electrical Safety Offices, etc, would do something about the trip current for domestic safety switches in Australia. Overseas research shows that child fatalities occur at currents as low as 8mA (see “Personnel Protection Devices for Specific Applications” by the Electric Power Research Institute, EPRI, Pleasant Hill, CA, USA). New Zealand research indicates that current as low as 5mA kills very young children. In the USA, domestic safety switches have a mandatory trip current of no higher than 10mA. In Australia, the trip current for domestic safety switches is 30mA. 10mA trip current safety switches are available in Australia Continued overleaf ... July 2001  3 but are not mandatory. The electricians have clearly been napping! By the way, what about this proposition: all homes should require an electrical wiring safety inspection when they are sold. That way, any dodgy wiring in older homes could be detected and fixed. After all, any home that is more than 40 years old probably needs a complete rewire anyway. Why wait for injury or fatality to expose a wiring problem? To summarise the campaign, we are appealing to the parliamentarians in each state to direct their electrical licensing authority to: (a) remove any restrictions which may prevent people from working on mains-powered equipment, whether it is for the purpose of service and repair, restoration or assembly; (b) produce legislation which is based on the New Zealand Electricity Act and Regulations, which allows householders to do their own “electrical work”, including appliance repairs and the installation of fixed wiring. You can do your bit to help by signing the “Statement of Will” in this issue and sending it to us. PLEASE DO IT NOW! Leo Simpson And now it’s all up to YOU! Send the completed forms to SILICON CHIP and we will forward them to the relevant state Ministers, along with copies of published correspondence, editorials, etc. The Ministers will be informed that their response, or a report that they apparently decided not to respond, will be published in SILICON CHIP! While in some ways similar to a petition, it must be our aim that it is not treated as a petition. If you have access to the Internet, go to http://www.rag.org.au/rag/petqld.htm and study the onerous requirements that must, by law, be observed in order to produce a petition that a state parliament will accept. Then click on Creative Petitioning at the bottom of the page to learn how easily parliaments can disregard petitions. Our state parliaments have refused to accept petitions that had many tens of thousands of signatures on them, simply because the form of the petition was not exactly correct. If you don’t have access to the Internet, suffice to say that conventional petitions to our state and federal parliaments are largely a waste of time. In addition to circulating the “Statement of Will” form, write an individual “MY WILL” letter, similar to the one below, to your local state member of parliament and encourage others to do the same. Don’t forget to date the letter and provide your name and address so the parliamentarian can confirm that you are a constituent. Dear Sir (or Dear Madam), I know that it is my duty to keep you informed of MY WILL on any matter that comes before Parliament, or that should come before Parliament. IT IS MY WILL that you take immediate action to end the “closed shop” that electricians enjoy in relation to “electrical work”, and that you promote the replacement of current electricity related legislation with legislation that is essentially equivalent to the New Zealand Electricity Act and Regulation, which allows householders to do their own “electrical work”, including appliance repairs and the installation of fixed wiring. Yours Faithfully, (signed) 4  Silicon Chip Above all, don’t enter into written argument with a politician. Politicians are masters in the art of avoiding what they don’t want to face up to, and become experts in manipulating words to their own benefit. Should your parliamentary member try to sidestep (and they are extremely adept at doing so) taking positive political action on your behalf (ie, they rattle on about what his/her party is or is not doing instead of agreeing to act in accordance with your WILL), you simply write back and state: Dear Sir (or Dear Madam), Further to my letter of (insert date of your original letter) and your reply of (insert date of their inadequate or fob-off reply), and in accordance with my lawful obligation to keep you informed of MY WILL, I again inform you that IT IS MY WILL that you take immediate action to end the “closed shop” that electricians enjoy in relation to “electrical work”, and that you promote the replacement of current electricity related legislation with legislation that is essentially equivalent to the New Zealand Electricity Act and Regulation, which allows householders to do their own “electrical work”, including appliance repairs and the installation of fixed wiring. Yours faithfully, (signed) If you have access to the internet, go to http://www.rag.org. au/ rag/mywillet.htm and learn about the background and potential power of the “MY WILL” letter. For each “MY WILL” letter you send to your parliamentary member, send a copy to SILICON CHIP so we can monitor the level of involvement in the campaign for reform. If your local parliamentarian shows interest in the issue, provide them with copies of relevant SILICON CHIP published correspondence and editorials, etc, or ask them to contact SILICON CHIP directly. Come on SILICON CHIP readers, you asked us to help you with this one – if you don’t want more and more restrictions, get those signatures rolling in! This information (including a copy of the "MY WILL" form) may also be downloaded from the SILICON CHIP website, www.siliconchip.com.au Statement of Will: Reform of Electrical Legislation The primary responsibility of parliamentary representatives and governments is to do the will of the people. Electors must make their will known to their parliamentary representatives and governments. We, the undersigned, hereby assert that it is our will that the government of *______________________________ acknowledge that current electrical safety legislation unjustifiably discriminates against ordinary householders as well as electrical and electronic engineers, technical officers, and technicians and that the effect of its enactment has been, and continues to be, to protect a monopoly for licensed electricians. We also hereby assert that it is our will that the government of *___________________________________ acknowledge that the potential dangers of “electrical work” are grossly exaggerated by the state electrical licensing boards and that the New Zealand electrical fatalities and accidents statistics belie these claims of dangers. We further assert that it is our will that the government of *______________________________________ repeal, in a timely manner, all current electrical safety legislation to replace it with legislation that is essentially equivalent to the New Zealand Electricity Act and Regulation, which allows ordinary householders to do their own “electrical work”, including appliance repairs and the installation of fixed wiring. * (insert state or territory)     Name           Address    Signature 1............................................. .......................................................................................................................................... ............................................................. 2............................................. .......................................................................................................................................... ............................................................. 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July 2001  5 Digital Amplifiers are here! Analog Audio could soon be dead! Audio recordings have been revolutionised by digital technology, which has allowed dramatic improvements in signal-to-noise ratio, distortion, wow/flutter and frequency response. Now the same kind of revolution is well under way in an area which many of us probably still see as the exclusive domain of analog circuitry: audio power amplifiers. By JIM ROWE 6  Silicon Chip W hen Compact Discs burst onto the audio scene in the early 1980s, they quickly changed the definition of ‘hifi’. Suddenly we had a recording and playback technology which could deliver a signal-to-noise ratio of 96dB, distortion levels below 0.01%, negligible wow and flutter and a frequency response which was near enough to ‘ruler flat’ over the complete audible spectrum. CDs delivered these benefits mainly because they took advantage of digital technology. Instead of trying to record audio waveforms faithfully in the grooves cut into vinyl records, they ‘sampled’ the waveform 44,100 times per second and turned it into a stream of binary numbers – ones and zeros – which could be recorded and played back much more faithfully. This made it possible to reconstruct a much more accurate replica of the original, when the digital samples were converted back into analog form. The same sort of benefits came when digital technology was applied to tape recording to provide us with DAT (digital audio tape). And the improvements continue, with the new enhanced digital recording techniques such as HDCD (High Definition CD), SACD (Super Audio CD) and DVD-Audio – which are just coming onto the market. But until very recently, the high quality audio available from these digital technologies still had to be converted back into analog for the last crucial step in the audio chain: power amplification to drive the speakers. That’s because up till now, analog circuitry has provided the only way to achieve a high-quality audio power amplifier. Sony’s Playstation 2, announced and released with such fanfare a few months back, contains a digital audio amplifier courtesy of Tripath. Sony’s new VAIO (Video Audio Integrated Operation) notebook computers also contain a similar digital audio amplifier. Even today, some audiophiles will tell you that the only kind of power amplifier worth listening to is one with a class A (or at worst, class AB) push-pull output stage, with a whopping great power supply, plenty of heatsinking and loads of negative feedback. And there’s the rub: traditional high quality analog power amps and their power supplies are big, heavy, expensive and wasteful of power. These disadvantages have been becoming more and more of a problem as manufacturers were pushed to make their products smaller, lighter, more efficient and of course, cheaper. Many products do need to incorporate audio power amps – and in some cases more of them than ever before, like home theatre systems and computer sound systems. So there’s been a huge amount of R&D effort invested in digital technology to achieve the kind of improvements with audio amps that it’s already provided in areas like recording and playback. Lofi digital The first digital amplifiers to come out of this R&D were pretty terrible and anything but ‘hifi’. Sure they were efficient but the signal-to-noise ratio was poor and most of them radiated so much switching noise that you couldn’t even bring a distortion meter near them, let alone measure their distortion level! In the last couple of years, though, that R&D has really begun to bear fruit. Many of the latest stereo TVs and home theatre systems from firms like Sony, Sharp and Hitachi now have true dig- This Evo 200-2 “bel canto” digital audio amplifier has been receiving outstanding reviews around the world – but then with its $US2395 price tag it would want to! Specs are 1Hz-80kHz, 240W RMS per channel. Unfortunately, though, one reviewer was a little over the top in saying it was at least as good as the best tube (valve) amplifier he had ever heard. . . July 2001  7 Tripath’s TA-3020 (right) and TA-2022 (below) digital amplifier driver chips. They’re already used in a range of consumer electronics equipment and they’ll be found more and more in the future. ital audio amps, as does Sony’s new Playstation 2 and its VAIO handheld computers. Apple Computer’s latest Power Mac G4 computers also use them, as do Altec Lansing’s latest PC speaker systems. Car audio firms like Alpine and Blaupunkt are using them in their latest models, and some of the new personal audio players and mobile phones are said to use them as well. Manufacturers like Sharp have even released true audiophile-level digital amplifiers, with specs that more than compare with the best traditional analog designs. The end of analog? In short, the writing is on the wall: the future of high quality audio amplifiers is eventually going to be digital, probably much sooner than most of us expected. Is this just because designers have found ways to get acceptable performance out of digital amplifiers or because they can get away with smaller heatsinks and power supplies? No, although those factors obviously help, it’s because digital amplifiers actually make more sense, now that so much audio material is being recorded and transmitted in digital form. With digital amplifiers the audio can be kept in this form right up to the high power level, ready to drive the speakers – which not only makes the whole system more efficient but provides the potential for even higher quality of reproduction (because there’s less signal processing). For example, audio is stored on the HD layer of the new SACDs in ‘Direct Stream Digital’ form, which is already 8  Silicon Chip how designers have been able to come up with digital amps which achieve true hifi performance, as well as very high efficiency. Let’s see how they’ve done it. How they work suitable for passing directly through many of the new digital amps. In fact, this is the best way of achieving the full enhanced audio performance from SACDs, rather than converting the signal back into analog form and feeding it through a traditional analog amp. The same applies to normal CDs and the new DVD-Audio discs, even though their LPCM (linear pulse-code modulation) audio has to be passed through additional upsampling and other digital processing circuitry. Even compressed multichannel digital audio like Dolby Digital, MPEG2 and DTS bitstreams can give better results, as the decoding and other processing can again all be done in the digital domain where they introduce far less noise and distortion. So there are compelling reasons for digital amplifiers. In a couple of years, just about all new consumer equipment is likely to have digital amps. Probably diehard audiophiles will keep using traditional analog amps (hey, some are even still using valve analog amps!) but eventually.... By now you’re probably wondering Digital amplifiers don’t handle multi-bit LPCM digital audio – the kind of 16-bit samples that come from a CD or the higher resolution 24-bit samples from DVD-Audio. Not directly, anyway. They handle a ‘bit-stream’ or single-bit digital signal. Single-bit signals have been used in recent years to make many of the highest quality digital master recordings. Well known examples are Philips’ Bitstream, Matsushita’s MASH and Sony’s Super Bit Mapping (SBM). Another general name for this format is Sigma-Delta Modulation (SDM), and it’s used for making master recordings because it’s actually capable of much higher fidelity than LPCM. The resolution can be equivalent to 24 bits or better, with a frequency response of DC to 100kHz and a dynamic range of over 120dB, as a result of noise-shaping techniques. To produce normal CDs, master recordings made using SDM are converted into PCM by digital processes known as decimation and brick-wall filtering. This inevitably causes some degradation, which is why Philips and Sony decided that to ensure higher fidelity on SACDs they would directly record the SDM bitstream – renamed Direct Stream Digital. Part of the reason why SDM can deliver much higher fidelity is that it’s a lot simpler to convert analog audio into SDM, than in a conventional multi-bit analog-to-digital converter. This is done by a Sigma-Delta modulator. As you can see from Fig.1, Sampling Clock (fc = 64 x fs) MIXER ANALOG INPUT + NOISE SHAPER & INTEGRATOR QUANTISER PDM OUT – (NEGATIVE FEEDBACK) Fig.1: A basic sigma-delta modulator, which converts analog audio into a PDM digital bitstream. They’ve been used for years as A/D converters for making digital master recordings. ANALOG INPUT Similarly, any analog audio signals must first be converted into PDM using sigma-delta modulators, before they can be amplified (see Fig.4). So this is the basic way digital amps work. But, as you might expect, the various manufacturers have made their own modifications to enhance the performance. Let’s look a little more into the technology of practical digital amplifier chips. Tripath’s DPP PDM BITSTREAM OUTPUT Fig.2: How the pulse density in a PDM bitstream corresponds to the amplitude of the original analog signal. this consists of an analog mixer, a noise-shaping filter/integrator and a quantiser. Think of the quantiser as essentially a comparator which is gated by a high frequency clock signal, and driving a storage flipflop. Typically the clock frequency is 2.8224MHz, or 64 times the 44.1kHz sampling rate used for CDs. Because of the negative feedback loop, the integrator’s output represents the difference between the input voltage and the digitised output from the previous sample, accumulated over the 354ns sampling period. So the quantiser’s next output will be a 1 if this accumulated difference is positive (ie, the input voltage rose slightly), or a 0 if it’s negative. The output from the modulator is therefore a single pulse train of bits at the 2.8224MHz clock rate, with their density representing the instantaneous amplitude of the original audio waveform. This is shown in Fig.2. Another name for this kind of A/D conversion is pulse density modulation or PDM. As well as being a very simple and direct method of A/D conversion, sigma-delta modulation has much higher inherent linearity than a multi-bit A/D converter. As a result of the very high sampling rate it also doesn’t need sharp-cutoff ‘brickwall’ filters to prevent aliasing. And although the basic modulator shown in Fig.1 does tend to have a poor signal-to-noise ratio, it turns out that this can be dramatically improved by using ‘higher order’ noise shaping circuitry. This involves additional feedback and integrators, with the effect of shifting most of the noise up and out of the audio range. The signalto-noise ratio in the audio range (even up to 100kHz) can thus be improved to 120dB or so. Finally, a PDM bitstream has another huge advantage over multi-bit LPCM: it’s much easier to perform digital-to-analog (D/A) conversion. In fact, with PDM you don’t need a complicated D/A converter at all, just a simple low-pass filter after the power amp’s output switching, as shown in Fig.3. In fact, Fig.3 is so simple that you can see why digital amplifiers are going to take over. PDM makes everything a lot easier – it’s still a true digital signal but one that’s very easy to convert back into analog. Virtually all the new digital amps handle the digital audio as this kind of single-bit stream, so apart from the DSD audio from SACDs, all other kinds of digital audio have to be converted into this form by over-sampling and other digital processing. +V One of the leading players in producing ‘hifi’ digital amplifier chips is Tripath Technology, a fairly small firm in Santa Clara (California) founded in 1995 by semiconductor industry veteran Dr Adya Tripathi. Tripath chips are being used in Sony’s DAV-S300 compact home theatre system, in the Playstation 2 video game box and VAIO computers, and also in Sony’s new plasma screen TVs. Apple Computer is using Tripath digital amp chips in its latest Power Mac G4 computers, as is Hitachi in its own new 81cm plasma screen TVs. Marantz and Carver are apparently using Tripath chips in some of their latest hifi amps, while they’re also being used in car audio systems from firms like Alpine and Blaupunkt. Tripath describes its digital amps as having a ‘Class T’ configuration, to distinguish them from early ‘Class D’ digital amps which used fairly basic pulse-width modulation (PWM) technology. They stress that a Class T amp is very different from a PWM amp, both because of its output configuration and because it pre-processes the incoming digital bitstream using their patented Digital Power Processing (DPP) technology. They’re rather coy about the exact PDM OUTPUT ANALOG OUTPUT Q1 PDM INPUT MOSFET DRIVER CIRCUIT L Q2 SPEAKER C PDM TO ANALOG CONVERTER! –V Fig.3: A major advantage of using PDM for digital amplification is that it can be converted back to analog simply by passing it through a simple low-pass filter. July 2001  9 BASIC DIGITAL AMPLIFIER +V PDM INPUT FROM SACD, ETC PDM OUTPUT ANALOG OUTPUT Q1 MULTI-BIT LPCM DIGITAL INPUT OVERSAMPLING DIGITAL FILTER ANALOG AUDIO INPUT SIGMA-DELTA (S-D) MODULATOR MOSFET DRIVER CIRCUIT L Q2 SPEAKER C –V Fig.4: A very basic digital amplifier configuration. The amplifier can accept the PDM signal from a SACD player directly, but multi-bit digital audio and analog audio signals require some input processing. details but it appears that their Class T power amp is actually a high power sigma-delta modulator stage with feedback right around the power switching stage and high-order noise shaping. The DPP block which drives it appears to use a technique of digitally modulating the basic DPM bit-stream. Its clock signal frequency and exact timing are varied (from 200kHz up to 1.5MHz) with the sensed analog signal level, to pre-compensate for the switching limitations of the power Mosfets. So the power amp switches at around 1.5MHz for low output levels but slides down to 200kHz for full analog output. It seems to be a bit like spread-spectrum technology but the end result is very linear and ‘clean’ analog output after the final low-pass filter. Currently, Tripath makes three different integrated digital stereo amp chips, all with impressive specs. The lowest power TA1101B device is a 30-pin PSOP package measuring only 11 x 16 x 3.4mm but it gives 2 x 10W RMS into 4Ω loads at 0.04% THD+N (distortion and noise) running from 12V. The efficiency is about 80%, so it needs only minimal heatsinking – an array of vias under the package, to conduct heat from its heat slug through to a copper pattern about 10 x 32mm on the other side of the PC board. At the other end of the range is the TA2022, which is a 32-pin SSIP package and delivers 2 x 90W RMS into 4Ω loads at 0.1% THD+N, running from ±35V and with almost 85% efficiency. For even higher power applications Tripath also make digital amp 10  Silicon Chip drivers, which provide everything for a complete Class-T stereo power amp apart from the power switching FETs. There are four of these amp drivers, one of which (the TA0104A) teams up with suitable power Mosfets to deliver up to 2 x 500W RMS into 4Ω loads (or 1000W in bridge-mode mono), at 0.05% THD+N and running at ±92V. You can find more information about Tripath’s digital amplifier devices at their website; www.tripath.com They have data sheets and application notes you can download as PDF files, along with white papers. Their patents are also available from the US Patent & Trademark Office website, at www.uspto.gov/patft/ Apogee’s DDX Another leading player in the digital amp field is Apogee Technology, of Norwood in Massachusetts. Apogee’s amplifier chips are used in Altec Lansing’s latest PC speaker systems and the firm also has a strategic partnership with European chipmaker STMicroelectronics to develop their technology jointly. Apogee’s chips are based on their patented Direct Digital Amplification or ‘DDX’ technology, which as the name suggests is designed to take a direct digital audio input and carry out all necessary processing and amplification in the digital domain. A feature of DDX is that it carries out special processing to convert the incoming digital audio into a pair of modified PDM/PWM bitstreams. These are then used to drive the output switching Mosfets in a special way known as ‘damped ternary’, to give high efficiency and improved audio performance. Instead of the two levels (1 and 0) in a normal binary waveform, the pair of digital signals produced by the DDX processor drive the Mosfets to produce a signal with three levels: +1, 0 and -1. (Hence the name ternary, meaning ‘of three parts’.) This output signal has much less switching noise and sampling clock content than a standard PDM/PWM signal, especially at low signal levels. Not only that, the speaker load ends up being much better damped as well, giving better transient performance. Fig.5 shows how with a normal PDM AudioSource’s “Amp Seven”, a 200W/8Ω (500W mono bridged) digital amplifier which uses Tripath’s Class T technology. Distortion is less than 0.01% and it is stable into 2Ω loads. It accepts standard (ie analog) input signals but processes digitally. (www.audiosource.net). +V Q1 DIGITAL OUTPUT HAS FULL RAIL-TO-RAIL AMPLITUDE EVEN FOR ZERO ANALOG OUTPUT (0V) (0V) PDM OR PWM INPUT MOSFET DRIVER CIRCUIT L Q2 SPEAKER C –V Fig.5: With standard PDM or PWM, the amplifier’s digital output signal has a very high ‘RF’ content even for zero analog output. This calls for large filter components to get the electromagnetic interference down to acceptable levels. or PWM binary drive signal, a binary 1 switches on one output Mosfet (s3ay Q1) to apply the full positive supply voltage to the speaker (via the low pass filter), while a binary 0 level switches on the other Mosfet Q2 to apply the full negative supply voltage. These are the only two output levels available, but the amplifier switches back and forth between them at a very high rate to provide an average level which varies with the audio output waveform –after it’s filtered, of course. Note that for all audio signal levels between peak positive and peak negative, the output Mosfets have to be switched on in turn during each clock period (or in alternate clock periods, with PDM) in the time ratio necessary to give the right instantaneous average level for the audio waveform. So for zero output voltage, they must each be switched on for 50% of the time – giving a very low audio voltage after the output filter. However, at the same time there will be a very high level of sampling clock signal (and its harmonics) at the input to the filter. DDX neatly avoids this problem when it converts the PDM signal into the drive signals for its ternary form. The processor works out the degree to which the two output levels would cancel each other at the output when they were averaged, and then it removes this part of the digital signal in advance. So only one or the other of the output Mosfets is turned on during that sampling period, for a proportion of time which gives the right average value. Or if the audio waveform should have a value of zero at that instant, neither main Mosfet is turned on at all. Fig.6 shows the idea, using an a 4Ω load, again with less than 1% THD+N and running from 28V. To make a complete digital stereo amplifier, a DDX-2060 is driven from the DDX-2000 controller chip. This is a 44-pin quad plastic flat package measuring only 10.5 x 9.5 x 2mm. It provides all of the processing to convert a serial multi-bit digital audio signal (from say an S/PDIF receiver) into a stereo pair of Apogee’s ternary drive signals – to drive each channel of the 2060. The DDX-2000 also provides a digital volume control function, managed by an external controller via an I2C bus. Apogee provides details of a complete 5.1-channel surround sound amplifier system which uses three DDX-2000 controller chips to drive four DDX-2060 power amp chips. With the controller chips running from 3.3V and the power chips from 28V, this configuration can take the serial digital signals from a Dolby Digital decoder chip and provide 4 x 35W for the FR, FL, SR and SL speakers, 35W for the FC (centre) speaker and 70W for the LFE subwoofer. A single volume microcontroller can adjust both master volume and channel balancing. The second of Apogee’s DDX controller chips is the DDX-4100, which provides all of the processing to provide DDX drive signals for five separate DDX power amp channels (ie, 4.1 channels of surround sound audio), from two different types of digital input signal: either S/PDIF (Sony/ Philips Digital Interface) stereo, or I2S/AC’97 (a Microsoft development) four-channel inputs. This means that one DDX-4100 can drive three DDX-2060 power amp chips to provide an all-digital 4.1-channel surround sound amplifier for PCs, delivering 4 x 35W plus 1 x H-bridge output switching circuit. As you can imagine, this reduces the level of clock signal ‘RF’ at the amplifier’s output dramatically, and makes it possible to use significantly smaller values of L and C in the filter circuit. In addition, though, the DDX power switching driver circuit itself pulls a neat trick. When neither of the ternary drive signals is at the 1 level, it turns on the two lower output Mosfets (ie, Q2 and Q4). So instead of getting any output energy, the speaker voice coil has a low resistance connected across it: the ‘on’ resistance of the two lower Mosfets (typically a fraction of an ohm) plus the DC resistance of the filter inductors. This applies heavy damping to the voice coil, which improves its transient behaviour. (Editor’s note: we don’t quite believe all that but a simple damping test would show if it was true.) The net result of the DDX technology is a digital amp which has very good signal-to-noise performance, low RF radiation and good speaker damping, while still offering very high electrical efficiency even at low signal levels. Apogee offers a single DDX stereo power amplifier device, which can be driven by either of two DDX processor/controller chips. The DDX-2060 power amp is a 36-pin package measuring 16 x 11 x 3.6mm. It can deliver 2 x 35W RMS into 8Ω loads with less than 1% Another AudioSource model, the “Amp THD+N, running from 28V. Six” modular dual-channel (stereo or Alternatively, it can deliver bridged mono) digital amplifiers again using 70W in mono mode into Tripath’s Class-T technology. July 2001  11 +V Q1 DDX 'DAMPED TERNARY' DIGITAL OUTPUT HAS NO PULSES FOR (0V) ZERO ANALOG OUTPUT (PDM) L1 Q2 PDM INPUT SPEAKER (LPCM INPUT) DDX PROCESSOR DDX DAMPED TERNARY DRIVE SIGNALS DDX POWER SWITCHING CIRCUIT C +V Q3 (ANALOG AUDIO INPUT) L2 Fig.6: Apogee’s DDX technology pre-processes the PDM/PWM bitstream to remove the ‘cancelling’ components, so the output switches produce a ‘damped ternary’ pulse waveform with much lower RF content. The lower Mosfets (Q2, Q4) are also turned on to heavily damp the speaker between the pulses, giving better transient performance. 70W of high quality audio at over 85% efficiency. The DDX-4100 also provides sample rate conversion, digital bass, treble and volume controls, bass management for the LFE channel and parametric equalisation for all five channels. All this comes in a 44-pin TQFP package measuring 10mm square! Apogee’s website at www.apo-geeddx.com provides full data on their chips and a white paper on DDX technology. Incidentally, you might be wondering what the difference is between "4.1 channel" surround sound and "5.1 channel" surround sound. 4.1 channel sound is basically what you get from matrix-type ’analog’ surround decoders like Pro-Logic: front left and right, plus centre front (basically L+R) and a single surround channel (basically L-R), with the ‘0.1’ channel carrying the bass from the centre front channel, LP filtered to run a subwoofer. On the other hand 5.1 channel sound is usually that from a digital decoder, with discrete FR, FL and FC front channels, two surround channels (SR and SL), and a discrete ‘low frequency effects’ or LFE channel for the subwoofer. The term ".1" is used to indicate 12  Silicon Chip Q4 the fact that the frequency response of that channel is deliberately limited to cover bass frequencies only; this channel is invariably used by the subwoofer. Only the start... Tripath and Apogee are not the ony firms working on all-digital amplifier chips. Cirrus Logic has just released a new Crystal ‘TrueDigital’ PWM amplifier controller chip, the CS44210, which is a complete digital stereo amplifier apart from the output switching Mosfets and their driver ICs. It provides all processing for up-sampling and sample-rate conversion from up to 24-bit digital inputs, digital volume, bass and treble controls, muting and de-emphasis, and even low power digital outputs to drive stereo headphones – all in a 24-pin TSSOP package measuring just 7.8 x 4.4 x 1.1mm. Together with a set of driver chips and power Mosfets, the CS44210 forms a digital stereo amp with 2 x 50W output into 8Ω loads, with an output dynamic range of 100dB and an energy efficiency of 90%. You’ll find full data on the Cirrus chip at www.cirrus.com Texas Instruments has released a LP FILTER (DAC) low-power PWM amplifier chip, the TPA2000D2 (2 x 2W RMS into 4Ω at 5V), with higher rated versions due shortly. Both Motorola and National Semiconductor have announced similar products, while Philips plans to have digital amp chips available later in the year. Other firms are already active at the equipment level. Last year, for example, Sharp Corporation released its SM-SX100 single bit 2 x 100W stereo amp offering true audiophile quality with a breathtaking $25,000 price tag. This year they’re releasing two mini stereo systems using the same all-digital technology and outputs of 20W/channel and 25W/channel respectively, with price tags below $3000. It’s very likely that most of the main consumer audio manufacturers will announce digital amps and systems before long, so prices will soon plummet. The digital amplifier era has definitely begun. Before the year is out you could be to be listening to one in your car, lounge room or computer room – or in your Walkman or mobile phone. Welcome to the all-digital audio future! SC This month’s special Video editing made easy! Networked and Wireless Here’s just some examples of how you can tap into this great system... Scenario 1: Set up a LAN of wireless networked PC’s. Connect notebooks and/or PC’s in difficult to wire environments such as historic buildings or frequently changing environments in retail shops, etc. Scenario 2: Provide access to corporate facilities such as email and data bases for Cat. 11339 mobile workers e.g. doctors and sales staff. Scenario 3: LAN interconnection for point-to-point link e.g. building to building. Cat. 11339-7 Access Point $1283 Cat. 11349-7 W/less LAN Acc. Point - Bridge $1349 Cat. 11340-7 PCMCIA Station Adapter - Internal Antenna $544 Cat. 11343-7 PCMCIA Station Adapter - External Antenna $598 Cat. 11344-7 PCMCIA to PCI Adapter $98 Cat. 11351-7 Directional Antenna $219 Cat. 11351 Cat. 8946 Bar Code Portable Laser Data Collector Count your stock or collect remote data with this portable laser barcode scanner. It is unbelievably small, about the size of a Nokia 5110, and the laser scanner is fast and accurate. It is easily programmed with a built-in program generator or the Windows based task generator. An LCD display provides the user interface along with a 26 key keypad. Uploading is via an RS232 connected cradle or an infrared link. To top it off, it has a Lithium Ion Cat. 8919 Battery so that problems associated with memory effects are largely overcome. Battery charging is automatic when placed in the cradle. price includes the data collector, cradle, & programming software. Cat. 8946-7 Portable Laser Data Collector $2280 Also our keyboard wedge & serial CCD scanners Cat. 8916-7 KB Wedge AT-PS/2 $243 Cat. 8919-7 Long Range CCD Scanner $443 USB to USB Network Cables These USB-USB Network Bridge Cables provide a quick and easy solution to networking up to 17 USB computers with hot Plug & Play technology without adding any Network Interface Cards, or instantly transfer files using "Norton Commander" type software (PC-Linq) via a split window system with the Interlink USB cable. Cat. 9125-7 USB Network up to 17 USB computers $87 Cat. 9107-7 USB PC to PC Interlink $66 Printer Servers Connect your digital video camera to your PC, download your video to the hard drive then kick in the Ulead Video Studio DV SE editing software provided. Follow the time line, edit your video, add transitions, etc... When finished simply write back to the tape. It's easy, effective & best of all...no loss of quality! Cat. 2621-7 Firewire Card & Software Normally $239 Now you can avoid slowing down a work station when a This month only $209 print job is running by installing While stocks last these small printer servers. Printer Servers essentially replace networked PCs used to service print jobs. Cat. 11352-7 Single Parallel Port 10/100Mb $338 Surveillance Cards Cat. 11293-7 3 Parallel Port 10/100Mb $358 A PCI PnP card with four composite video inputs. It has Win95 & Win 98 drivers & is bundled with MultiMulti-PC Controllers cam Remote Viewer, Digital Surveillance System & Save time, space and money Backup System software. Features include: by using one keyboard, moni• Zoom-in / Zoom-out function tor and mouse to control up to • Brightness, Contrast, Saturation, Hue controls Cat. 11654 sixteen PCs. Our Multi-PC • Programmable multiple detection zones for each Controllers are available to control 2, 4, 8 or 16 PCs camera. & operate in DOS, Win 3.x/9x/ME/NT/2000, • Motion-Detection and Recording / Storage of Netware UNIX and Linux environments. PC selec- Video Data / Communication. tion is via a push button or keyboard hot keys. • Multiple Alarm Triggering mode. Cat. 11654-7 2 way PS/2 $199 - Alarm from speaker. Cat. 11655-7 4 way PS/2 $389 - Alert message call to your pager or phone call. Cat. 11656-7 8 way PS/2 $949 $1280 Cat. 11655 Cat. 3429-7 4 Camera Input Cat. 11657-7 16 way PS/2 $1299 Cat. 3466-7 8 Camera Input $2440 Cat. 3448-7 12 Camera Input $3480 Cat. 3449-7 16 Camera Input $4399 Cat. 11656 TERMINALS Cat. 11657 Hard Drive Controllers Cat. 2848 Ultra DMA100 IDE controllers are available as standard or Text Terminals RAID. Will co-reside with up to Replace your aging termi4 additional onboard IDE nals or install new systems devices! using industry standard monitors and keyboards. Cat. 2827-7 Ultra DMA100 $129 Our terminals emulate a wide range of industry ter- Cat. 2848-7 Ultra DMA100 RAID $154 minals, including WY-120/60, 325, 50+; TV1910+ / 925, ADDS A2, PC TERM, PCG ALPHA, VT52, 100, YOUR 220; and Console ANSI. Standard VGA monitors and SELF keyboards plug straight into the back of the termiNew courses now on line - SAP R/3, nals. The terminals are available with either a serial from a low WIN2000 MCSE, RPG, Web design, $1595 connection or an ethernet connection. CCDA LAN/WAN, e Commerce. Cat. 1133-7 Terminal 460K Serial $549 per month www.tol.com.au Cat. 1134-7 Terminal TCP/IP Ethernet $579 TRAIN Windows Based Terminal Save on your system & support costs and considerably enhance your security. On a Windows Based Terminal system, all the processing is done on the server, the terminal only receives screen updates. There are no floppy drives or PC operating systems to corrupt. Simply connect over your ethernet network, via modem or even over the internet. The terminals support Microsoft’s RDP and Citrix ICA protocols, in addition to emulating a number of standard terminals (VT100 etc). Cat. 1214-7 Terminal Windows Based $1069 ONLINE Training Online Phone: 02 4389 8800 email: info<at>tol.com.au We welcome Bankcard, Mastercard and VISA NO SURCHARGE! Phone: (02) 4389 8444 sales<at>mgram.com.au info<at>mgram.com.au Australia wide express courier $ 12 (3kg max) FreeFax: 1 800 625 777 MicroGram Computers Dealer Enquiries Welcome! Unit 1, 14 Bon Mace Close, Berkeley Vale NSW 2261 Vamtest Pty Ltd trading as MicroGram Computers ABN 60 003 062 100. July 2001  13 MGRM0701-7 All prices subject to change without notice. COMPUTERS: Do-it-yourself & learn A PC TO DIE FOR Part 2: installing the operating system & squashing the bugs By GREG SWAIN Last month, we showed you how to build a great PC based on a 1GHz Athlon CPU and an Asus A7V133 motherboard. This month, we’re going to show you how to partition and format the hard drive and install Windows Me (WinMe) as the operating system. 14  Silicon Chip terfere with the CPU fan. If this stalls, you’ll get a distinct burning money smell as the CPU “fries”. Switching on I NSTALLING THE OPERATING system on a new computer is usual­ly quite straightforward – a piece of cake, in fact. If you haven’t been through the process before, here’s your chance to learn. We’re going to describe the installation of Windows Me but the procedure is pretty much the same for other operating systems. Basically, it involves a 5-step process: (1) Tweak a few motherboard BIOS settings; (2) Partition and format the hard disk drive; (3) Install the operating system; (4) Install specialised device drivers, as necessary (eg, for graphics and sound cards); and (5) Connect to the Internet and down­ load any critical updates for the operating system. OK, we’re about to turn the computer on for the first time but before doing so, it’s a good idea to remove the sound card. Yes, we know that we instructed you to install this card last month but experience has shown that it’s best to install the operating system first, then add the sound card later. The same applies to any other devices. Now take a good look at the system and check that every­thing is correct. In particular, make sure that all the drive cables and power connectors are plugged in and that nothing can in- Now for the smoke test – hook up the mains power leads and switch on. If everything is OK, the system will go though its Power-On Self Test (POST) routine. First, it should show the type of video card used (at the top of the screen), along with the amount of video RAM (32MB for the board specified). It should then correctly identify the motherboard BIOS version and the processor before going through the memory test procedure. At this stage, you should press “DEL” to get into the BIOS Setup Utility. This will take you directly to the Main menu, as shown in Fig.1. What we’re going to do now is change a few of the BIOS settings so that everything is identified and works correctly. The BIOS Setup Utility is easy to navigate – just use the arrow keys to jump from one setting to the next (and from one Menu screen to the next) and press <Enter> to bring up a sub-menu when you want to change a setting. The -/+ keys are then used to change the setting, after which you hit the <Esc> key to take you back to the previous menu. It’s hardly the stuff of rocket sci- ence and you’ll soon become adept at finding your way around, even if you’ve never ventured into a BIOS setup screen before. Anyway back to the main chase. Begin by setting the system time and date to the correct values, then check that the floppy disk drive (ie, Legacy Diskette A) has been correctly identified. This done, you have to “tell” the system what drives are hanging off the primary and secondary IDE ports. Now this bit is important – these two IDE ports have nothing to do with the two Ultra ATA100 IDE ports that are also on the motherboard. In fact, the Ultra ATA100 ports are not covered by the Award BIOS – in­stead, they have a separate BIOS chip on the motherboard and are detected later during the boot process. In our machine, the only item to be covered here is the DVD-ROM drive which is connected as a master to the primary IDE port. As a result, we set the Primary Master drive type to “Auto” (for auto-detect) and this show­ed up as “ATAPI DVD-ROM 16X Maxim” after we hit the <Esc> key to take us back to the Main menu. If you have any other drives hanging off the IDE ports, these can be set to “Auto” (for auto-detect) as well. Alterna­ tively, you can choose the Fig.1: this is the main BIOS setup screen. You set the system time and date here and adjust the settings for the primary and secondary IDE ports. In our case, the DVD-ROM drive was on the “Primary Master” IDE port – see text. July 2001  15 cannot change them – at least not when the “Operating Frequency Setting” is set to “Standard”. The “DRAM Frequency” setting defaults to 100MHz to ensure system stability. However, provided that you’ve used 133MHz SDRAM, you can bump this setting up to match (ie, to 133MHz) to squeeze a bit more performance. Overclocking Fig.2: the Advanced menu shows the settings for the CPU clock multiplier and bus frequency. In this case, we are using a 1GHz processor and the settings are 10.0 and 100MHz respectively (10 x 100MHz = 1GHz). Because we are using PC133 SDRAM, the DRAM frequency has been bumped up to 133MHz. For those interested in overclocking, changing the “Operat­ing Frequency Setting” to “User Define” lets you tweak both the CPU clock multiplier and frequency settings. You can manually set the multiplier anywhere in the range from 5.0x to 12.5x, while the CPU frequency can be tweaked in 1MHz steps over the range from 100MHz to 166MHz (note: this was incorrectly stated as 133MHz last month). Bus frequency settings of 90MHz and 95MHz are also available. Our advice here is simple – DON’T DO IT! If you want to play around with overclocking, at least wait until the operating system is installed and everything is working correctly. Even then, we don’t recommend over­ clocking unless you know exactly what you are doing. Actually, we think that the performance gains to be had from overclocking are so small as to not warrant the in­creased risk of system instability and CPU damage. The same goes for the “CPU Vcore Setting” – leave it on the default Auto setting unless you know what you are doing. Most other settings here can be left on the defaults. You can refer to the motherboard manual for more information on these. Boot sequence Fig.3: this is the Boot setup menu. Move the CD-ROM to the top of the list if you have an OEM or full retail version of the operating system. The floppy drive should come first if you are installing an upgrade version. drive “type” if devices other than hard disk drives are involved; eg, CD-ROM, ZIP-100, etc. What about the Quantum Fireball hard disk drive used in our machine? Well, that’s connected to the primary Ultra ATA100 IDE port and is automatically detected during boot-up, so we don’t have to enter any special settings. Next, flick across to the Advanced menu (just press the left arrow key) 16  Silicon Chip and check the settings shown in Fig.2. Assuming that you configured the Asus motherboard in JumperFree mode as described last month, these settings should all be automatically identified and should be correct. In particular, for a 1GHz CPU the “CPU Clock Multiplier” will be set to 10.0x, while the “CPU Frequency” will be 100MHz – ie, 10 x 100MHz = 1GHz. Actually, these two settings will be “greyed out”, which means that you OK, now let’s flick across to the Boot menu and sort out the boot sequence (Fig.3). This determines which drive the system boots from and your choice will depend on whether you’re installing a full retail version or an upgrade version of the operating sys­tem. If you have a full retail (or an OEM) version, you can boot directly off the CD-ROM. The system will then pretty much au­ tomatically partition and format the hard disk for you, prior to installing the operating system. Conversely, if you are installing an upgrade version, you have to boot from a Windows Me (or Windows 98) startup floppy. You then have to manually partition and format the hard drive yourself. After that, you need to reboot from the startup floppy to load the necessary drivers for the CD-ROM drive, so that the operating system can be installed. It all boils down to this – if you have a full retail or OEM version of the operating system, place the DVD-ROM drive at the top of the boot order. Alternatively, if you are using an upgrade version, place the floppy disk drive (Legacy Floppy) at the top. While you’re at this menu, set the Plug & Play O/S to “yes” (assuming you’re using Windows 98/Me/2000) and disable the boot virus detection feature. The setup procedure is going to write to the boot sector of the drive when installing the operating sys­tem, so we don’t want any false alarms here (you can re-enable the virus protection when setup is complete). Once that’s done, flick to the Exit menu, save your changes and exit from the BIOS Setup Utility. Fixing Up The Video Driver Fig.4: this is the display that greeted us the first time Windows Me booted. This occurred because WinMe installed a generic video driver running at 640 x 480 and 16 colours. Fig.5 (left): the System Properties dialog box confirms the type of video card driver installed. It also shows a problem with the “PCI Mass Storage Controller”. Operating system versions Before going further, let’s clear up a misconception that many people have about “full” and “upgrade” versions of an oper­ating system. An upgrade version is in no way “inferior” to a full version. The main difference between them is that you cannot boot from an upgrade CD-ROM and it doesn’t include the partition­ing and formatting tools included in the full version. An upgrade version also performs a “compliance” check during installation, to confirm that you already have an earlier version of Windows. Naturally, if you are “clean installing” an upgrade version onto a new hard disk, there will be no evidence of the previous operating system. The way around this is to “show” the system the CD-ROM for the earlier version when prompt­ed to do so during the compliance check routine (see panel), after which the installation will proceed normally. Apart from that, an upgrade version is identical to a full version and in­ stalls exactly the same system onto the hard disk. Partitioning and formatting We’ll assume here that you have an OEM or full retail ver­sion of Windows Fig.6 (below): the new video driver is a snack to install – just auto-run the driver CD & click Install Driver. Me. Begin by inserting the WinMe CD-ROM in the drive, then restart the machine and choose “Boot from CDROM” and “Start Windows Me Setup from CD-ROM” from the resulting menus. The setup procedure will now automatically partition and format the disk drive. Be sure to choose “enable large disk support” when prompt­ed. This installs the FAT32 file system which is necessary for the operating system to recognise large disk partitions. By contrast, the older FAT16 file system limited partition sizes to 2.1GB and that’s hardly enough these days. A FAT32 file system also reduces cluster size (down from 32KB to 4KB) and that means less disk wastage. Installing Windows After formatting, the system will automatically reboot and run Scandisk before going to the Windows Me Setup menu to install the operating system. This basically involves a 5-step process, as follows: (1) Preparing to run Windows Setup; (2) Collecting information about the computer; July 2001  17 The Gentle Art Of Hard Disk Partitioning The most common method of partitioning a hard disk drive is to create one large “Primary DOS Partition” which occupies all the disk space. However, many people prefer to “split” their hard disk drive into two partitions, so that it looks like two (or more) individual drives (eg, C: and D:). Why would you want to do this? Well, there are several reasons. First, it allows you to keep your work files completely separate from program and system files. This makes accidental deletion of vital program and system files far less likely, makes it much easier to do routine data backups and allows for faster defragging of the work “disk”. Second, splitting a hard disk drive into multiple parti­tions is the way to go if you want to set up a dual-boot or triple-boot operating system. For example, you might want a dual-boot system that lets you to choose between Windows Me and Wind­ows NT, or between Windows Me and Linux. By far the best way to set this up is to install each operating system into its own partition. Basically, you can split a hard disk drive into just two partitions: (1) a Primary DOS Partition; and (2) an Extended DOS Partition. The primary partition becomes the C: drive but you can create as many logical drives in the extended partition as you wish. Fig.7: the fdisk utility is menu driven, so you’ll have no trouble finding your way around. You can either create one primary DOS partition, or split the disk into two separate partitions – primary and extended. (3) Copying Windows files to the computer; (4) Restarting the computer; and (5) Setting up hardware and finalising settings. It might look a tad intimidating but it’s really all bounc­ing ball stuff that’s easy even for a novice to follow. Most of the procedure is automatic and you just have to fill in a few details and make a few choices along the way. In particular, you have to fill in the “Product Key” (found on the back of the CD-ROM case) and choose the type of system you want installed when you get to the “Setup Options” menu – either Typical, Portable, Compact or Custom. Take my tip and go for the Custom setup. This lets you add components that are not installed by 18  Silicon Chip If you install an OEM (or full) version of WinMe on a new hard disk, the setup routine will automatically create a single “Primary DOS Partition” on the hard disk. So how do you create multiple partitions? The answer is that you have to manually create the parti­tions using the fdisk utility (this is included on the CD-ROM). To do this, you boot from the CD-ROM as before but this time you select “Start Computer With CDROM Support” from the menu (in­stead of “Start Windows Me Setup from CD-ROM”). This boots the computer to a DOS prompt and creates a “RAM disk” with the system tools in it. Typing fdisk initially brings up a Fig.8: if you answer “Y” here, fdisk creates one primary DOS partition that occupies all the available space. Answering “N” lets you specify the size of the primary partition and then create an extended partition. default and delete space-consuming features that you don’t want. My advice is to leave out as much clutter as possible. This includes unnecessary stuff such as Destop Themes wallpaper, sounds, fancy mouse pointers and other features. After all, why slow down a PC by loading wallpaper or other fancy background themes? Always keep your desktop clean and simple – you’ll get better performance if you do. For the same reason, you should also later resist the temptation to have lots of programs automatically start up at boot time. Everything you load runs in the background and hogs system resources, so keep as much stuff out of the Startup folder as possible. Other stuff that can usually go are the Accessibility items and the Online Services. You can also deselect “Disk Compression” (found under System Tools) if you don’t intend running compressed disks. While you’re here, it’s usually not a bad idea to select the following items: Character Map, Clipboard Viewer, Net Watcher (for monitoring network connections if you have a network); System Monitor and System Resource Meter. A lot of the items under “Communications” can also be dese­lected but be sure to select “Dial-Up Networking” if you intend connecting to the Internet. You should also select “Internet Connection Sharing” if you intend using the machine to share an Internet connection with other machines on a network. dialog box that asks whether you wish to enable large disk support (ie, the FAT32 file system). It’s necessary to answer “Y” (yes) here if you want the operating system to “see” partitions greater than 2.1GB. After that, the screen shown in Fig.7 appears and you simply follow the menus to partition the drive. Assuming an unpartitioned drive, you first select option 1 to create a DOS partition and then option 1 again to create a primary DOS partition. If you allocate all of the disk space to the primary partition, then that’s the end of the matter and you finish up with just one logical drive (ie, C:). Alternatively, if you allocate only part of the space to the primary partition, you can then create an extended partition to cover all or some of the remaining disk space. After that, you can create one or more logical drives in the extended partition. These logical drives automatically take on the next drive letters in the sequence (ie, D:, E:, etc). Typically, you might want to split a 20GB hard drive so that it has a 6GB primary partition and a 14GB extended partition with a single logical drive. This means that your machine would appear to have two hard disk drives – a 6GB C: drive and a 14GB D: drive. Of course, you can make the partitions any size you want. By the way, you have to set the C: partition as the “Active” partition. This designates which partition con­tains the boot sector – ie, it determines where the boot files are stored. Once the partitions have been Fig.9: this screen shows the partition information for a 1.6GB drive that’s between split into two partitions. The primary partition occupies 65% of the drive space, while the extended partition occupies the remainder. It’s largely a matter of personal preference as to what you keep and leave out. And, of course, you can always add wanted items and delete any unnecessary features after the operating system has been installed (this is done using the Add/Remove Programs utility in Control Panel). Along the way, you will be directed to create a Startup disk so be sure to set aside a clean floppy disk before starting the installation. You’ll also be prompted to choose a keyboard type – the US 101-key keyboard is the one to go for in Australia. At this stage, the system will begin copying files to the hard disk drive. This will probably take 20-30 minutes or more, depending on the speed of your CD-ROM drive. created, you need to format each of the logical drives in turn. You’ll find the format utili­ty (format.com) in the \WinMe folder on the CD-ROM, so you’ll need to change to this folder before running this command. For example, let’s say that you have two logical drives (C: and D:) and that your CD-ROM is at E:. First, you’ll need to change to the CD-ROM drive by typing E: <Enter> at the DOS prompt and then typing cd \WinMe to change to the \WinMe folder. Once there, you can format the C: drive by typing format c: at the prompt. When the format is complete, you can then format any remaining drives in exactly the same manner. It’s also a good idea to run the scandisk utility on each of the drives, to verify the drive integrity. Fig.10: if you make a mistake or change your mind, it’s just a matter of deleted the existing partition(s) and starting again. Warning: all data on a hard disk drive is lost when you alter partitions using fdisk. During this process, the Setup Wizard automatically re­ s tarts the computer several times and there’s a great deal of disk activity as the system identifies the hardware configuration and copies the relevant files across. Towards the end, you will be prompt­ ed for a password. If you don’t want a password, leave the password field blank. Final setup Once the installation is complete, the system should au­tomatically boot into Windows but there may be a few problems to solve. In our case, the system booted with a grey desktop as shown in Fig.4 – nothing like the default dark-blue desktop normally expected with WinMe. What’s happened here is that the system has installed a generic driver for the video card. That’s easily checked out in the Device Manager and this will also highlight any other prob­lems that may be lurking. In fact, once the system is running, the Device Manager should be your first port of call. You can start it by double-clicking the System icon in Control Panel and then clicking the Device Manager tab on the resulting System Properties dialog box. This lists all the items that are currently installed on your system and allows you to check that all devices are working cor­rectly. A yellow exclamation mark or a red cross next to any item indicates a problem. July 2001  19 Installing The Driver For The Promise Ultra ATA100 Controller Fig.12: the wizard automatically searches the CD-ROM for the best driver or you can specify the path to the driver yourself. Fig.11: the VIA 4-In-1 drivers and the Promise Ultra 100 IDE Controller driver are installed from the CD-ROM supplied with the motherboard. The CD-ROM auto-starts when placed in the drive. In our case, the Device Manager revealed two problems – see Fig.5. First, it showed that a “Standard PCI Graphics Adapter (VGA)” had been installed for the video card (something that we already expected). Second, it showed that we needed to install a driver for something called a “PCI Mass Storage Controller”. These two problems were easily solved. First, the video driver – this is supplied on a CD-ROM which auto­ starts to bring up the dialog box shown in Fig.6. Clicking the “Install Driver” button then did the trick. This automatically installed the correct driver, after which the machine booted to a nice blue desktop. The “PCI Mass Storage Controller” that WinMe found during setup is actually the Promise Ultra ATA100 IDE controller. Get­ting this working correctly is just a matter of installing the drivers from the CD-ROM supplied with the motherboard. This CD autostarts to the dialog box shown in Fig.11. In­stall the “Via 4-in-1 Drivers” update first, then install the driver for the Promise Ultra ATA100 controller. Actually, click­ing the but20  Silicon Chip Fig.13: this list shows the drivers found by the automatic search routine. Choose the one that matches the installed operating system. ton here doesn’t automatically install the driver. Instead, it brings up a small text file which instructs you how to do this manually. The procedure is straightforward – select the “PCI Mass Storage Controller” entry in Device Manager, click the Properties button and select the Driver tab to update the driver. You can then either do an automatic search for the driver or manually specify the driver’s location (Fig.12). An automatic search eventually brings up the dialog box shown in Fig.13 and it’s then just a matter of selecting the driver that matches the operating system (WinMe in this case). Manually specifying the location of the driver is quicker though – you just browse to the folder that has the driver. In our case, the required driver is in D:\Promise\ATA100\WINME (D: is the drive letter for the CD-ROM drive). Once we’d done all that, the driver entries for the video card and the Promise Ultra ATA100 Controller appeared as shown in Fig.14. Note that the Promise driver is listed under SCSI con­trollers, even though it’s not a true SCSI device. This is per­fectly normal. Fig.14 also shows the driver entries that appeared after we installed the sound card. Fig.14: this is what the System properties dialog box looks like after the correct drivers have been installed for the video card and the Promise Ultra 100 IDE Controller. Installing other drivers If any other devices are causing problems, you can update the driver in exactly the same manner. Usually, it’s just a matter of clicking the Update Driver button in Device Manager and then letting the system automatically search for a driver on the CD-ROM or floppy disk supplied with the device. If it finds more than one driver, it’s then simply a matter of choosing the cor­rect one for your operating system from the list. Alternatively, you can manually specify the location of the driver by browsing to the correct folder on the CD-ROM or floppy disk yourself. Be sure to check out any readme files on the driver disk for installation instructions. Another technique for dealing with problem devices (ie, those with yellow exclamation marks or red crosses beside them) is to remove them from the Device Manager and reboot. The system will then rediscover the new device as it boots and prompt you for the driver disk. Again, you can do an automatic search for the driver or specify the location yourself. Setting the display resolution Once you have the correct driver installed for the graph­ics card, you’ll want to set the display resolution to something better than the 640 x 480 default. To do this, right-click on the desktop and choose Proper­ties to bring up the Display Properties dialog box Adjusting The Display Properties Fig.15: this screen grab shows the default display settings that were installed by Windows Me. It installed a generic video driver at 640 x 480 pixels and just 16 colours. Fig.16: once the correct video driver has been installed, you can adjust the display settings as shown here. Clicking the advanced button gives you lots of other settings to play with. (Fig.15). Now click the Settings tab and drag the slider to the right to increase the display resolution. A resolution of 1152 x 864 is about right for a 17-inch monitor but you can vary this to suit yourself – see Fig.16. While you’re here, you will also want to change the number of displayed colours from the drop-down list to the left of the slider. Depending on your graphics card, choose either “High Color (16-bit)” or “True Color (32-bit)”, then click the Apply button. Windows will then resize the desktop for 15-seconds, after which you can Clean Installing The Windows Me Upgrade Version If you are clean installing an upgrade version of WinMe onto a hard disk, you won’t be able to boot from the CD-ROM. This means that you’ll need a WinMe or Win98 startup floppy in order to start your system. These startup floppies also include the necessary utilities to allow you to partition and format the disk drive, and include drivers for CD-ROM support. If you’re upgrading from an old computer, you’ll need to make a startup floppy before trashing the system. It’s easy enough to do – just insert a floppy disk in the drive, open “Add/Remove Programs” in Control Panel, click the Startup Disk tab and then click the Create Disk button. If you’ve already trashed the system, you’ll have to beg, borrow or steal a startup disk from somewhere. But be careful – you don’t want your new machine to start life with a virus on board. Note that you will have to change the system BIOS, so that the floppy disk drive is first in the boot order. If you don’t do that, the system will try to boot from one of the other drives first and you’ll get a “Non-system disk” error message. When you boot from the startup disk, a menu appears giving you the option to start the computer with or without CDROM support. The startup floppy first loads the CD-ROM driver (if this option is selected), then loads a 2MB RAM drive. This RAM drive includes format.com plus several diagnostic tools. Note that the RAM drive will push your CD-ROM drive back one letter. This means that if your CD-ROM is usually drive D:, it will now become drive E:. In any case, an on-screen message tells you what the drive letters are, so you don’t have to figure it out. After that, you can partition and format the drive(s) in the usual manner. You then boot the machine with CD-ROM support, switch to the CD-ROM drive and type Setup at the command prompt to run the Windows Me installation wizard. During installation, the system will perform a “compliance” check to make sure that you’re entitled to use the lower-cost product. Typically, it does this by checking the hard disk drive for an earlier version of the operating system but you can also install an upgrade version onto a freshly formatted drive. How? – easy; just insert the CD-ROM for your earlier version when prompted to do so. If you are upgrading from Win98 to WinMe, for example, all you have to do is “show” the system your Win98 CD-ROM for com­pliance checking. In fact, you can even show a Win98 upgrade CD-ROM (eg, if you’ve previously used this to upgrade from Win95) and the system will be happy with this. Once compliance checking is complete, you re-insert the upgrade CD-ROM and the installation proceeds as normal. July 2001  21 Fig.17: the Folder Options dialog lets you set Windows up to satisfy your personal preferences. Fig.18: clicking the “View” tab gives you other options to choose from. Choose the options that suit you best. choose to either accept or discard the new settings. Clicking the Advanced button will allow you to change the monitor driver and to adjust other parameters specific to the graphics card. In our case, the Philips 107S monitor (which is Plug ’n Play) was correctly identified and its driver installed during the WinMe setup, so we didn’t have to bother with this. If you have a different monitor, then it may be necessary to install the driver yourself from the supplied CD. Windows Me directly supports DVD-ROM drives, so there is no need to install additional drivers for this device. You might, however, want to install the software that’s supplied with the DVD-ROM drive (this will install a DVD player (Fig.23). Installing the sound card Now let’s get that sound card going. Power off, plug the card into a vacant PCI slot (don’t forget to connect the audio cable from the DVD-ROM drive) and switch on. The system will find the new hardware as it boots and prompt you to install the driver. It’s then just a matter of placing the Sound Blaster Live CD-ROM in the drive, and specifying the location for the driver on the CD-ROM by browsing to D:\ AUDIO\ENGLISH\WIN9XDRV. Alternatively, you can allow the Fig.19: clicking the “Performance” tab in the System properties dialog box should show the message “Your system is configured for optimal performance”. system to automatically search for the driver and then select the correct driver from the resulting list. The system will then complete the reboot, after which your sound card should be fully functioning. By the way, there are lots of other goodies on the Sound Blaster CD-ROM for you to install. Just re-insert the CDROM to auto-run the install dialog box and go from there. You’ll probably also want to install Acrobat Reader so that you can read the Sound Blaster manual that’s on the CD-ROM. Other hardware items (eg, ZIP drives, CD-ROM burners, network cards, etc), can now be added to your new PC. It’s always best to install these Asus Probe: Watching Over Your System’s Health Fig.20: the Asus Probe summary screen let's you check the system “health” at a glance. 22  Silicon Chip Fig.21: this screen lets you set the alarm thresholds for the CPU and motherboard temperature. There’s lots of “goodies” with the sound card Fig.22: the SoundBlaster sound card comes with a bewildering array of software, including “Rythmania” (above), “Media Ring Talk” for Internet phone calls (top, right) and a Surround Mixer, Recorder, Play Center and Application Launcher (right). There’s lots more, as well. Fig.23: the DVD-player software installs this dedicated DVD-player utility. one at a time and get each new device working before installing the next. tab on the System Properties dialog box – see Fig.19. Personal preferences Asus Probe There are a few adjustments that you might like to make to the appearance of the desktop, to satisfy your personal preferences. For example, if you want a Windows classic desktop rather than web-enabled content, just click Tools -> Options in Explorer to bring up the Folder Options dialog box shown in Fig.17 and make your selections. It really is a matter of personal preference here. Clicking the View tab brings up the dialog box shown in Fig.18. Personally, I always like to select the “Show hidden files and folders” options and choose not to “Hide file extensions of known file types” (ie, I want to see the file extensions). You should also check that your system is configured for optimal performance by clicking the Performance It’s a good idea to install the Asus Probe utility from the motherboard CD-ROM. This handy utility runs in the background and continuously monitors the system “health”, in- cluding the CPU fan speed, the CPU and motherboard temperatures and various voltage levels. It can be set to launch automatically at system startup and could save you big bucks if there’s a simple hardware failure. That’s it – don’t forget to visit the Windows Update site when you’ve finished. You should also download and install any updated device drivers; e.g, SC for the video card.ZIP-100, etc. RAID 0 vs RAID 1: Disk Striping & Disk Mirroring As stated in Pt.1 in the June issue, the Promise controller on the Asus A7V133 motherboard supports a feature called “RAID 0”. The article then went on to describe RAID 0 as disk mirroring but this is incorrect. RAID 0 (also known as “data striping”) is actually a technique that “stripes” the data across two identical disk drives. It allows you to combine the two drives into one logical partition and splits the data evenly between them. This effectively doubles the data transfer rate because only half the data is written to each drive and the drives operate in parallel. The setup procedure is fully described in the manual. The downside is that RAID 0 offers no data protection at all. In fact, it actually increases the risk of failure because if one drive fails, all the data on the RAID array is lost. The disk mirroring technique referred to in Pt.1 is actually known as RAID 1 and is not directly supported by the Asus A7V133 motherboard. July 2001  23 SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.dicksmith.com.au HEARTMATE Build it & keep tabs on your t icker Got a treadmill or exercise bike to help you keep fit? How do you know whether you are overdoing it? Build this Heart Rate Monitor and stop yourself carking it. You can monitor your pulse beat rate to maintain it within certain limits. There is a timer to limit the duration of your exercise, minimum and maximum pulse rate buzzers and a recovery rate display. By JOHN CLARKE 28  Silicon Chip Y EAH, YEAH we know there are plenty of miniature heart rate monitors for people who want to jog but they don’t include all the handy features of the SILICON CHIP Heart Rate Monitor. It will display pulse rates up to 235 beats/minute and has a number of preset buzzers to help you in your exercise program. A Heart Rate Monitor is an essential piece of equipment when you are exercising as you can maintain your pulse rate at the desired level. Fig.1 shows target pulse rates for people aged between 20 and 70. The target range is the pulse rate needed in order to provide suitable exercise for the heart. For a 25-year old, this range is about 140-170 beats per minute while for a 60-year old it is typically between 115 and 140 beats per minute. It is important not to overdo it. If you begin to feel weak and light headed, stop immediately. The SILICON CHIP Heart Rate Monitor has an audible buzzer which can be set to sound if your pulse rate falls outside the target range that you set. And having exercised within the target range for a preset time, a buzzer will sound to tell you to have a rest. Feeling completely knackered? The SILICON CHIP Heart Rate Monitor will monitor your recovery. This is the time to recover to your normal resting pulse rate after the exercise period. If you are really fit, your recovery time will be quick and if you are not (like most of us), it will be a lot slower. The SILICON CHIP Heart Rate Monitor is housed in a small plastic case which can be mounted onto the handle bars of your exercise machine, be it an exercise bike, treadmill or whatever. It is powered from a 9-12V DC plugpack so there are no bat­teries to go flat. The 3-digit display uses 7-segment LEDs which are bright and easier to see than small LCD units. It has three pushbuttons to control its operation and a column of LEDs to indicate the current function or reading on the display. The pulse detector is a finger stall with an inbuilt in­frared LED and infrared detector. The finger stall is held onto your finger with a strip of Velcro (hook and loop). The Heart Rate Monitor shows pulse rates from 26 beats per minute to 235 beats per minute on its 3-digit display. If your pulse rate is below 26b/m you are either a lizard or you are dead. Fig.1: this diagram shows the target pulse rates for people aged between 20 and 70 when undertaking exercise. For a 25-year old, the range is about 140-170 beats per minute, while for a 60-year old, the target range is about 115-140 beats per minute. Either way, it will be displayed as “Err” on the display. Actually the most likely possibility is that the finger-stall is not properly attached to your finger. At the other end of the scale, measured pulse rates above the 235b/m limit will be displayed as three dashes (---). When the heart detector is working properly, the top-most LED in the LED column flashes in unison with each pulse. The 3-digit display is updated on every second pulse. When the pulse Main Features •  Ideal for use with exercise machines •  Adjustable timer with buzzer •  Visible pulse indicator •  Timer end buzzer •  Timer stops below minimum •  •  •  •  pulse beat rate Start/stop timer control Recovery display 1,2,3,4 & 5 minutes Error display for no pulse Minimum & maximum pulse settings for audible buzzer rate is being displayed, the second LED in the column is also lit. A piezo buzzer will momentarily sound if your pulse rate goes above or below preset values. The Timer setting can be displayed by pressing the rate/timer switch and this also lights the Timer LED in the column display. The SET switch is used to display the three presets. Press­ ing the SET switch selects the minimum pulse rate display and lights up the “Rate min” LED. The minimum pulse rate value can then be adjusted using the up and down pushbuttons. The inbuilt (default) setting is 130b/m. Once a new value is selected, it is stored in memory regardless of whether the power is on or off. Pressing the SET switch again lets you set the maximum pulse rate and also lights the “Rate max” LED. The inbuilt set­ ting is 160b/m. The SET switch will also display the timer setting and light the Timer LED. Then you can adjust the setting from one minute to 255 minutes (4 hours 15 minutes) in one-minute steps using the up and down switches. The initial setting is 30 minutes. To start the timing period, press the Start/Stop switch when the display is showing either the pulse rate or July 2001  29 The circuit is built on two PC boards which are stacked together inside a standard plastic utility case. Power is supplied by a 12VDC plugpack. current timer setting. The timer will count down from its preset value if the pulse rate is above the minimum setting and the LEDs in the column will begin chasing. When the buzzer sounds, a LED will flash to explain the warning. For example, if your pulse is racing above the set maximum, the buzzer sounds and the “Max rate” LED flashes. Similarly, if there is an error in detecting the pulse, the display will show “Err” and the “Rate min” LED will flash. This will stop the exercise timer. You can start the timer again with the Stop/Start switch but the timer will only begin counting down when the minimum pulse rate has been reached. The buzzer will also sound when the timer has counted down to zero. Recovery mode At the end of the timer countdown, the Heart Rate Monitor goes into the Recovery mode. For the next five minutes the dis­play will show REC, then the current timer value, then REC and the current pulse rate. The corresponding Pulse Timer LEDs will be displayed as each reading is shown. At one-minute intervals, the buzzer will sound and current heart beat rate will be stored in memory, referenced to the current minute. If there is an error in the reading, then the pulse value will be zero. At the beginning of the recovery 30  Silicon Chip period, the minute display will show “-0” to indicate that the timer is less than one minute into the recovery period. After one minute the display will show “-1” and then -2, -3, -4 and -5 at each successive minute. At the end of the five minutes, the display changes to show the pulse rates stored at each minute interval. The display will show REC, then “-0” and then the stored pulse rate. It then shows “-1” and the next stored pulse rate and so on. The display will continue to cycle through these values until either the unit is switched off or a switch is pressed. Pressing a switch will return the unit to the pulse mode. Circuit description Now let’s have a look at the circuit of Fig.2. IC1 is the PIC16F84 microcontroller which is the heart of the circuit. Three 7-segment displays DISP1DISP3 and a bargraph LED display DISP4 are driven directly from the RB1-RB7 outputs of IC1 via 150Ω limiting resistors. This is a multiplexed display ar­rangement with all the “a” segments on DISP1, DISP2 & DISP3 tied together and the same comment applies to the “b” segments and the “c”, “d”, “e”, “f” & “g” segments. The LEDs within DISP4 are tied to the “b”, “a”, “f”, “g”, “e” and “d” segments, respectively. The LED displays have their common anodes driven by tran­ sistors Q1-Q4 from the RA0, RA1, RA2 and RA3 lines of IC1. For example, if RA0 is brought low, transistor Q1 will be switched on to apply power to the common anode of the LEDs in DISP4. At the same time, a low output on RB1-RB7 will light the corresponding LED in the display. After DISP4 has been lit for about 1ms, the RA0 output is taken high and the RA2 line is brought low to drive Q2 and dis­play DISP1. The new 7-segment data on the RB1-RB7 lines is pre­sented to DISP1 for the next 1ms. Then the RA1 line is brought low to drive DISP3 and so on. Note that the “c” segment output from RB3 also connects to one side of the piezo transducer while the other side is driven by transistor Q1 via diode D5. However, the piezo transducer is driven only when DISP4 is on and only if the RB3 output is brought low at this time. If it is driven, it effectively Fig.2 (right): the circuit is based on a PIC microcontroller (IC1) which drives three 7-segment LED displays and a LED bargraph. IRD1 and RD1 form the infrared pickup – its output is processed by op amps IC2a-IC2d and used to drive the RB0 input of IC1 via transistor Q5. July 2001  31 Fig.3: follow this layout diagram to build the PC boards and complete the wiring. Note the orientation of switches S1-S3 – they are all mounted with their flat side to the left. Table 2: Capacitor Codes gets a 1ms pulse every 4ms, an effective frequency of 250Hz. Diode D5 isolates the transducer from the circuit if the RB3 line is high and Q1 is off. The 10kΩ resistor across the transducer discharges its capacitance between each forward pulse. The Set, Up and Down switches (S1-S3) are monitored by the RA4 input. These switches also connect to the RA2, RA3 & RA1 outputs respec- tively via diodes D2, D3 & D4. Normally, RA4 is held high via the 10kΩ resistor connected to the +5V supply. Depending on whether RA1, RA2 or RA3 is low when a switch is closed, IC1 will respond with a programmed action. Diodes D2, D3 & D4 are included to prevent the RA1, RA2 & RA3 lines from being shorted if more than one switch is pressed at the same time.  Value IEC Code EIA Code  0.33µF  334  330n  0.1µF  104  100n  .033µF   333   33n  15pF   15   15p IC1 runs at 4MHz due to the crystal (X1) connected to pins 15 & 16. This frequency is divided by four for the internal opera­ tion of the microprocessor. An internal counter further divides this by four and then by 250. The resulting signal drives the dis­ Table 1: Resistor Colour Codes           No. 1 7 2 6 1 3 4 1 7 32  Silicon Chip Value 2.2MΩ 1MΩ 100kΩ 10kΩ 2.2kΩ 1kΩ 680Ω 560Ω 150Ω 4-Band Code (1%) red red green brown brown black green brown brown black yellow brown brown black orange brown red red red brown brown black red brown blue grey brown brown green blue brown brown brown green brown brown 5-Band Code (1%) red red black yellow brown brown black black yellow brown brown black black orange brown brown black black red brown red red black brown brown brown black black brown brown blue grey black black brown green blue black black brown brown green black black brown The signal processing board is fitted with 15mm tapped spacers and is mounted in the bottom of the case by clipping it into the integral side slots. The display PC board is then secured to the tops if the spacers using machine screws. play multiplexing at 1kHz. Further division by 1000 provides us with a pulse once every minute which updates the timer. The pulse signal is applied to the RB0 input of IC1 which interrupts the program whenever this input goes high. Internally to IC1, there is a counter which counts how many 2ms intervals there are between two heart beat pulses. This number is then divided into 60,000 and the result is the pulse rate. For example, if the pulse rate is 60b/m (beats per minute) there will be a pulse every second. The duration of two heart beats will be two seconds or 1000 x 2ms. Dividing 1000 into 60,000 will give the correct result of 60 which is shown on the display. The actual update period for the pulse display is once every second heart pulse. So the update is every 2 seconds at 60b/m, once every second for 120b/m and so on. Detection of the pulse is via an optically-coupled pickup using an infrared LED (IRLED1) and a photo diode (IRD1). The infrared LED is powered from the +9V supply via a 560Ω resistor and its light shines into the flesh of your finger and is reflected off the bone. The pulsating blood through the vessels modulates the amount of light being detected by the infrared diode IRD1. Op amp IC2a is connected as a current-to-voltage converter for IRD1 which exhibits a varying reverse current in response to the changing light from the finger. The anode of IRD1 and the non-inverting input to IC2a is biassed at +4.5V. Pin 9 is the inverting input and the cathode of IRD1 connects to this via a 1kΩ stopper resistor. The gain of IC2a is set by the 1MΩ resistor between pin 8 and the cathode of IRD1 while the .033µF capacitor provides high frequency rolloff above 4.82Hz. This is to attenu­ate 50Hz mains signals which might otherwise be amplified. Note that there is also a 2.2MΩ resistor from the cathode of IRD1 to ground. This makes IC2a function as an inverting DC amplifier with a gain of -0.45 and this causes pin 8 to sit at about +6.5V. The resulting current through the 1MΩ resistor to the 2.2MΩ resistor is enough to provide a very The piezo transducer is secured to the bottom of the case using machine screws and nuts, while the DC power socket is mounted on the side. Make sure that none of the mounting screws can foul the PC board. July 2001  33 Fig.4: here’s how it all goes together inside the plastic case. The snap-in locators in the case guides hold the PC boards in place. small reverse bias current through IRD1 and thereby ensure that it works at maximum sensitivity. The output of IC2a is AC-coupled via a 0.33µF capacitor, giving a low frequency rolloff below 0.48Hz or the equivalent of 29 beats per minute. IC2b has a gain of 11, set by the 1MΩ feedback resistor and the 100kΩ resistor connecting from pin 6 to the +4.5V rail. The 47µF capacitor provides a rolloff below .03Hz. The .033µF ca- pacitor across the 1MΩ resistor gives the same high frequency rolloff as in IC2a. IC2c is almost identical to IC2b except that it includes a gain control, VR1. IC2c’s output is AC-coupled to op amp IC2d which is connected a Schmitt trigger, by virtue of the positive feedback applied by the 1MΩ resistor between pins 12 & 14. The output drives the base of transistor Q5 via a 10kΩ resistor to provide the The U-shaped metal bracket on the back of the unit allows it to be attached to the handlebars of an exercise bike or treadmill. 34  Silicon Chip pulse signal to pin 6 of IC1. Power for the circuit comes from a 9V or 12V DC plugpack via diode D1 and power switch S4, to feed two 3-terminal regula­tors. REG1 produces +5V while REG2 produces +9V. The 9V supply is divided by two series 1kΩ resistors to give a +4.5V supply to bias the inputs of IC2. Construction The Heart Rate Monitor is constructed on two PC boards. Board 1, coded 04107011 and measuring 105 x 62mm, contains the displays and microcontroller, IC1. Board 2, coded 04107012 and measuring 105 x 62mm, contains the amplifier circuitry for the pulse sensors. The two boards are stacked together and housed in a plastic case Fig.5: the mounting clamp details. It attaches to the base of the case using two M3 x 20mm screws and M3 nuts. Making The Infrared Pickup Sensor Fig.6 (left): how the infrared pulse sensor is made. The infrared transmitting and receiving LEDs are fitted side-by-side into two slots that are cut into a PVC saddle clamp section. Below: the pulse sensor assembly is fitted with a length of Velcro so that it can be held in position on your finger. You can use contact adhesive to secure the Velcro to the PVC section. measuring 130 x 67 x 44mm. The full wiring details for both boards are shown in Fig.3. Begin construction by checking the PC boards for shorts between tracks or any breaks in the copper connections. Compare the patterns with the published artwork to be sure they are correct. Check hole sizes. The corner mounting holes and regula­ tor tab mounting holes should be 3mm in diameter. The holes for the PC stakes should be drilled to give a tight fit for these. You can work on both PC boards together. Insert the PC stakes first, followed by the links and resistors. Use the resis­tor colour codes in Table 1 when selecting the resistors and use a digital multimeter to check each one before it is installed. Next, insert and solder in the diodes, making sure that they are oriented correctly. Note that D1 is a 1N4004. The 7-segment displays July 2001  35 Parts List 1 PC board, code 04107011, 105 x 62mm 1 PC board, code 04107012, 105 x 62mm 1 front panel label, 125 x 63mm 1 plastic case, 130 x 67 x 44mm 1 transparent red Perspex or Acrylic sheet, 56 x 18mm x 2.5mm 1 DC panel socket (plus self- tapping screws if required) 1 9V or 12V DC 300mA plugpack 3 snap-action keyboard switches (S1,S2,S3) 1 miniature SPST rocker switch (S4) 1 4MHz parallel resonant crystal (X1) 1 piezo transducer 1 18-pin DIL socket 4 M3 x 15mm tapped standoffs 10 M3 x 6mm screws 2 M3 x 20mm screws 1 M3 x 6mm countersunk screw 6 M3 nuts 2 M2.6 x 15mm screws 2 M2.6 nuts 1 small rubber grommet 1 crimp eyelet with 3mm eyelet hole 13 PC stakes 1 25.4mm saddle clamp 1 200mm length of 25mm wide hook and loop tape (Velcro) 1 20mm saddle clamp (used for conduit) 1 10mm length of 12.5mm diameter heatshrink tubing 1 120mm length of 0.8mm tinned copper wire 1 50mm length of red medium duty hookup wire 1 50mm length of black medium duty hookup wire are inserted with the decimal point facing toward the switches. DISP4 should be inserted with the label side towards IC1. Insert the socket for IC1 with its pin 1 oriented as shown in Fig.3. IC2 can be soldered directly into the PC board. Now insert the capacitors. The electrolytic types must be oriented correctly with the positive side placed as shown on the overlay diagram and with each one laid over on 36  Silicon Chip 1 50mm length of green medium duty hookup wire 1 800mm length of single core screened cable (small diameter type) 1 100kΩ horizontal trimpot (VR1) Semiconductors 1 PIC16F84P microprocessor programmed with HEART.HEX (IC1) 1 TL074 quad op amp (IC2) 3 LTS542A 7-segment common anode red displays (DISP1DISP3) 1 DIL 10-LED (red) bargraph (DISP4) 1 photo interrupter for IRLED1 (Jaycar Cat. Z-1901 or equivalent) 1 IR photo-diode BP104, BP104, (IRD1) 1 7805 5V 1A regulator (REG1) 1 7809 9V 1A regulator (REG2) 4 BC328 PNP transistors (Q1-Q4) 1 BC338 NPN transistor (Q5) 1 1N4004 1A diode (D1) 4 1N914, 1N4148 switching diodes (D2-D5) Capacitors 1 100µF 16VW PC electrolytic 2 47µF 16VW PC electrolytic 5 10µF 16VW PC electrolytic 3 0.33µF MKT polyester 2 0.1µF MKT polyester 3 .033µF MKT polyester 2 15pF NP0 ceramic Resistors (0.25W, 1%) 1 2.2MΩ 3 1kΩ 7 1MΩ 4 680Ω 2 100kΩ 1 560Ω 6 10kΩ 7 150Ω 1 2.2kΩ its side, as shown in the photographs, to allow the PC boards to be stacked. For the same reason, the crystal is placed on its side and is secured at its free end using a short length of tinned copper wire soldered to the PC board. When inserting the pushbutton switches make sure that the flat sides are oriented as shown. The four transistors Q1-Q4 should be inserted so that their tops are level with the top of the dis­plays. Q5 is the BC338 and it does not need to be inserted so far into the PC board. REG1 & REG2 are mounted horizontally and the tabs are secured with an M3 screw and nut. The boards stack together as shown in Fig.4, with 15mm tapped spacers and M3 x 6mm screws. The integral side slots in the case must be cut away for the first 13mm to allow the assem­ bly to slide into place. Drill a hole in the end of the case for the DC power socket and drill another hole at the other end for the rubber grommet required for the pulse sensor leads. Use the front panel artwork as a guide to drilling the holes for the switches and to make the display cutout. The cutout is drilled and filed so that the red Perspex or Acrylic window is a tight fit. Attach the front panel label and cut out the holes in this with a sharp knife. Drill two holes to mount the piezo transducer on the base of the case and drill a central hole for the sound to escape. The details of the mounting clamp are shown in Fig.5. It attaches to the base of the case with two M3 x 20mm screws and M3 nuts, as shown in Fig.4. Sensor details Fig.6 shows how the pulse sensor is made. A section is cut from a 20mm PVC conduit saddle clamp and two slots cut into it install the IR sensors. The IRLED is taken from the IR interrupt­er assembly by carefully breaking the plastic housing in which the LED is secured. The IR LED is the one which has the diode symbol embossed on the top of the plastic housing. You can break the housing carefully with pliers and side cutters to release the LED. We do not use the detector within the housing since this is a photo transistor and is not suitable for detecting the small light changes involved. Cut the saddle clamp as shown in Fig.6 and mark, drill and file the rectangular slots for IRLED1 and IRD1. IRD1 should be able to pass through the hole so it is flush with the inside surface of the saddle clamp. The IRLED is best positioned so the rear face of the package is flush with the outside of the clamp. We used an eyelet as a cable clamp for the wires and this is attached with The pulse sensor should be wrapped firmly around your finger, to ensure a reliable pickup. Note that the sensor should go over the fleshy part of the finger, not over the bone as some bonehead has shown here. a countersunk screw which taps into the PVC material. Wires can be soldered to the IRD1 and IRLED1 leads after passing them through the eyelet crimp end. We used some spaghetti sleeving to protect the wires from the clamp. The leads are then secured in place with a 10mm length of 12.5mm diameter heatshrink tubing. Testing Connect the DC plugpack to the socket and check that there is a nominal 5V between pins 5 and 14 of the socket for IC1. There should also be 9V between pins 4 and 11 of IC2. If these voltages are correct, kill the power and insert IC1 into its socket. Make sure it is in the correct way. Apply power again and check that the display lights and the pulse rate LED lights. The pulse LED should flash on and off if you rapidly move your finger onto and off the sensor assembly. Placing the end of your finger over the sensor should make the pulse LED flash on and off (in time with your pulse) and a plus rate should be shown by the display. You may need to adjust VR1 to obtain sufficient sensitivity or it may need to be turned back for best results. Too much sensitivity can make the display show a higher figure than it should. You can set the minimum and maximum pulse rates using the graph of Fig.1 as a guide. The timer is set by selecting timer and adjusting the minutes displayed. Setting the timer to 60 will provide a timeout after 1 hour. You cannot set the timer to a value that’s less than 1 minute. Fig.7: here are the full-size etching patterns for the two PC boards. When the start switch is pressed, the value in the set timer will be transferred to the timer and it will begin counting down every minute. The three lower display LEDs in the bargraph should chase each other when the timer is counting down unless your pulse heart beat is above or below the preset maximum and minimum figures. You will need to make a finger stall with Velcro to hold the pulse sensor securely onto your finger while you SC exercise. Fig.8: this full-size front panel artwork can be used as a drilling template. July 2001  37 SERVICEMAN'S LOG The Televideo that committed hari-kari I’ve got rather a mixed bag this month, ranging from a Teac Televideo that committed hari-kari – or so my son claimed – to a DVD player that was sunk by U-571. One thing’s certain – granny won’t be lending her Televideo any more. Some years ago, I gave my mum a Teac Televideo (MV1440) for her birthday. It was perfect for her little bedroom and she could lie in there and watch her recorded soapies to her heart’s content. Recently, to everyone’s surprise and relief, my son actually got a job as a warehouse assistant. This was fine until one day the ancient warehouse roller door decided to jam in the open position. Unfortunately, the earliest anyone could replace the door was the following week, which meant the warehouse had to be left open to the world. The consternation about security concerns this caused management was enormous until my son, who had just learnt about overtime, put his hand up to be- 38  Silicon Chip come nightwatchman. This appealed no end to the management who eagerly agreed to this arrangement. My son quickly went home to get some essentials, like a six pack (of light ale) and his Walkman. He also persuaded his granny to lend him her prize Televideo – to get through the wee small hours. He arrived back at the warehouse, unloaded his van and proceeded to build a little nest in one corner of the warehouse which was in a good position to view the broken garage entrance. The TEAC was placed precisely on top of an old oil drum but unfortunately the reception was lousy with the indoor aerial. Apparently, he was fiddling with the aerial in an attempt to improve the reception when the accident happened. The way he tells it, it was the set that had deliberately committed hari-kari. The way I saw it, he had pulled the lead too hard and the set fell off the oil drum and landed very heavily on its back on the concrete. He brought it to me the next day, sheepishly pleading: “Please fix Gran’s telly . . . and please don’t tell her anything”. Well, I took it to the workshop but as soon as I had removed the back, I could see that the set was a write-off. The neck of the tube had broken and the motherboard was cracked. What could I do? I went around to a rival TV repair shop whose main line of business was buying, restoring and selling secondhand TVs. I’m on good terms with them and so I asked if by any chance they had a Teac MV1440 in stock. We went down into their warehouse and had a rummage. The only thing they had was an MV1480 MK II, which is a later model, but it did have some faults. Apart from being filthy and having the front flap missing, the set worked a bit. There was no sound and a washedout snowy picture on-air. The video was also working but there was just a snowstorm on playback. However, this all worked to my advantage in the price negotiations. Back at the workshop, I started with the video playback, which turned out to be very dirty heads. A careful wipe of the heads axially with a lintfree material and oil-free acetone cleaned them thoroughly. The sound fault was more difficult to find but in the end turned out to be an intermittently open-circuit loudspeaker. All I was left with was the snowy off-air pictures. First, I checked the aerial socket and for continuity to the extremely small Murata tuner. I then checked that the set was able to tune in all the stations on VHF and UHF, which it did – albeit slightly snowy. I then checked the RF AGC (it was about 6.5V) and found that the AGC control in the separate equally small IF module also worked but adjusting this didn’t clear the fault. Although I had the service manual for this model, the circuit is not drawn for the tuner or IF modules which are just shown as block diagrams. I was faced with a dilemma – was the tuner faulty or was it the IF module or both? I was satisfied that all the voltages into both were correct. The big downer in this progress was that the tuner alone had a trade price exceeding $108 and the IF unit over $172. To narrow things down, I connected another tuner in place of the original and found that the picture was more or less the same after retuning, which to my mind eliminated the tuner. I then removed the IF module and examined it. It consisted of an IC, several coils and ceramic filters, and several surface-mounted components, including three transistors. I checked the transistors and this revealed that the SAW filter driver (or first IF transistor) was open circuit. Unfortunately, I didn’t know its type number, so I had to try a different approach. I looked through a pile of scrapped TVs and videos, searching for a similar surface-mounted transistor which was performing the same function. I eventually found one in the IF stage of a Hitachi video and swapped them over. And that did it – after retuning and readjusting the AGC control, I could finally tune in perfect pictures. A bit of “Nifti” cleaner and some polish cleaned the rest of the set up nicely. Finally, I checked that the old remote control worked the newer model which it did. Granny was surprised to get back a different set but found that the new one gave a better picture. As for my son, he’s traded the repair for a few months of lawn mowing and other domestic duties. A crook Akai VCR Mr Jones brought in his Akai VSG425EA video, complaining that it was chewing up his tapes. Unfortunately, he didn’t bring in any of his tapes; nor was he clear what he was doing when the tapes got damaged. Fortunately, I have a large box of ruined tapes for such occasions. I removed the covers, put a tape in and it immediately laced up against the drum and played OK. It could also fast forward and rewind but was intermittently slow in bringing the tape back into the housing. It would also sometimes leave tape loose on top of the deck so that when you pressed eject, the cassette door would close, leaving the tape outside to get all “scrunched” up. My immediate assumption was that the idler reel was faulty and sticking and not providing sufficient torque to pull the tape in whenever the mechanism unlaced the video heads. I removed the whole deck which is very easy these days – undo five screws and pull three assorted plugs and sockets and it’s out (after you have removed the front escutcheon, of course). I removed the reel roller, examined it closely but could find nothing wrong to the eye. I put a new one in just in case and replaced the belt as well. Unfortunately, they made no differ- Items Covered This Month •  Akai VS-G425EA VCR. •  Teac MV1440 Televideo. •  Philips 14GR1224/75R TV set. •  Sony DVP-S735 DVD player. ence. The reels were running free, with no hindrance, so the problem had to be elsewhere. My eye now moved onto the next suspect, the mode select switch. This VCR isn’t very old and looks new with little wear. Mr Jones is an old age pensioner but doesn’t watch many video movies, so why would you expect trouble with a fully encapsulated rotary switch underneath the deck? Yeah, well I wish someone would tell me because replacing it fixed the problem completely. In fact, before I did that, I lightly squirted it with CRC 2-26 and that also fixed it. I then opened up the switch to have a good look inside. It looked immaculate, nice and clean with a transparent layer of light switching grease to protect the metal surfaces. Despite all this, apparently the contacts had gone high resistance, hence its early demise. Cleaning and re-lubricating them will work for a while, but clients demand much more these days! GRI-AX revisited Over the years, I have seen many Philips GRI-AX chassis TVs. By and large, they have been an excellent series of models which have performed July 2001  39 well and have been mostly easy to fix – that is, until recently! M r S o r e n s e n ’s 1 1 - y e a r o l d 14GR1224/75R was dead and he sensibly brought it in because it is a lightweight and it’s always easier to bring the set to the workshop rather than vice versa. The set was slightly corroded inside but consistent with its age, and it didn’t take long to work out that the flyback transformer and line output transistor were both cactus. Both were replaced and the set left on soak test for several days before Mr Sorensen came to pick it up. As is my policy on all TV repairs, if there are any dry joints in the set (and which set doesn’t have any?), I set to work and resolder them. The GRI-AX is very prone to dry joints, especially around I7020 and the line output stages, but after a thorough soak test, I was 40  Silicon Chip very confident that all would be well. But it was not to be. Three weeks later he brought it back in, saying it was dead again. I lent him another set and had another go at it. Intermittent problems with this model are invariably due to the SCR crowbar current switching on prematurely. By measuring the voltage across C2660, or more conveniently from the anode of the SCR6641 to ground, which should be 97V, you can then adjust VR3625 until the SCR fires – theoretically at about 101V or so. If it is less than this, I change zener diode ZD6640 from 30V to 33V, or even higher if necessary, and then repeat the adjustment. When satisfied it is firing at the correct point, I then reset the voltage for 97V or less. The other thing that should be done is to replace C2523 with a new 10µF capacitor and also replace C2542 and L5524. With all that done, I was feeling bullet-proof but this set only worked for another day before it died again and stayed dead. I was so glad it had happened in the workshop and not back at Mr Sorensen’s house. And I was even happier that it was now permanently dead because this gave me a better chance to nail the problem properly. I soon found that the remote control could switch the set on from standby, after which the red LED would go out. There would then be a “wimpish” noise from the set as it tried to come on, before ultimately failing. It was time for some voltage measurements. The full 97V was available right to the collector of the line output transistor (TR7528) but the 9V startup voltage was way down at about 6V. Using an oscilloscope, you could see the correct waveform start to build up all the way from pin 26 of IC7020, through TR7521, TR7523 and TR7528 – but it would always collapse almost immediately. The set is designed to start with 9V and then have the 12V take over from the flyback transformer via D6542. I had already replaced the flyback transformer (T5530) and the line output transistor (TR7528), so now I fitted a new IC7020 into a freshly soldered 28-pin IC socket. This made absolutely no difference so I then swapped the chassis with one from another nearly identical set that was also in for repair but the main chassis still refused to fire up properly. Grasping at straws, I next desolder­ed the sound output IC (IC7103), as this is often troublesome and can provide an unacceptable load when the set is attempting to start. This still made no difference. Finally, I connected an external power supply to the cathode of D6635 and wound it up to 10V before switching the set on. Bingo! – it fired up. I then removed the external power supply and the set remained on. Next, I switched the set to standby and then on again and it still worked. I repeated this many times until suddenly it wouldn’t start again unless an external power supply was connected to the 9V start-up rail. What was going on? My assumption was that this rail was too low for a successful startup sequence but after installing new diodes (D6635 and D6632) and several new electrolytic capacitors and getting nowhere, I decided to try a different tack. It was time for the hot and cold treatment, so I began by hitting the usual suspects with freezer to see if this would pinpoint the problem Now, I might add at this point that when the set did start on its own, the 9V rail was actually closer to 10V. It definitely wasn’t low, so I couldn’t help feeling this was a red herring. Anyway, it was while I was alternately freezing and heating components near the rear of the flyback transformer that I noticed the problem suddenly become more critical – like a doctor or dentist finding a sore spot on your body or mouth. Anyway, it seemed to me that the culprit was D6624. My circuit showed this to be a 4.3V zener diode but in actuality it was an 1N4148. I then realised I was looking at the wrong circuit diagram because in fact the set was GRI-AX version 2. I replaced the diode anyway and a few others nearby but the trail was becoming cold again. More soak testing was required before the fault re-occurred two days later and I repeated the hot and cold treatment. By now, I was beginning to realise that if the line drive signal was insufficient on startup, the set would not turn fully on. This might also be due to a lack of gain in transistors TR7521 and TR7523. I replaced the latter first with a BC547C, the original being a BC33740, but it made no difference. By now the set was again in one of its “let’s play dead” modes. I then replaced TR7521 (a BC368) with another BC547C, making sure that I bent the base lead around the collector lead to fit the leads in the correct holes. This time the set switched on perfectly. I measured the old transistor to find its collector-emitter junction was very leaky. I was delighted to have at last found a real faulty part and left the set to soak test with repeated on/ off switching for the next week before returning it to Mr Sorensen. Sunk by friendly fire A good friend of mine is an Australian of German extraction and is a fine technician, working for the local Sony agency. An English client brought his Sony DVP-S735D DVD player in, complaining that the disk drawer wouldn’t open. My friend showed him how to open it by pushing a lever underneath to release the drawer. The client did this but when he put the DVD back in, the drawer jammed shut again. My friend finally booked the unit in and examined it in the workshop. First, he noticed that without a disk in it, the drawer would open and close by itself quite normally and without duress. However, when the DVD was put in, the drawer jammed. The DVD played perfectly and did all the trick functions – it just wouldn’t release the disk. My friend removed the covers from the machine and tried to see what was happening. He could see the disk go in OK, the spindle locking magnets clamp in position and the laser focusing as the disk started to spin. All was fine, until he hit eject. The spindle locking magnets opened but instead of releasing the disk, the DVD was being held by the top magnet and was preventing the door from opening. It looked as though this particular DVD was magnetic! He tried half a dozen other DVDs and CDs and none of them gave any problem – it was just this particular DVD. And the name of the movie on this DVD? – it was “U-571”. Talk about being sunk by friendly fire! Now, I thought this was a damn good story – but there is a twist. My friend went home that night after fixing it and thought about it. In the end, he just couldn’t believe that the DVD disk could be magnetic – it stretches one’s credibility just too far. So the next day he went back to the set and re-examined the facts. The DVD player could play any other DVD/CD except “U-571”. What about trying it in another player? He did that and found that it would play on other machines, thus exploding his original theory – almost every other player uses the same magnetic clutch mechanism. So why wouldn’t “U-571” play on the Sony machine? Very careful examination under a magnifying glass showed there was a very fine film of “gunk” on both the DVD disk and the metal plate it was sticking to. The two surfaces were almost analogous to a 2-part epoxy glue. By cleaning both surfaces very carefully, he was able to then play “U571” on the Sony machine without it sticking to the magnetic metal plate. So I guess the answer is obvious – SC always keep it clean! July 2001  41 O P T O PA C K 1 0 4 D E V I C E S : various colours & types. Top brands. Siemens etc. just $10 VISIBLE LEDs...5mm...14X Yellow clear, 6X Red (clear) 24deg, 2X Yellow (clear) 24deg, 16X Red (clear) 24deg,38X Green (clear) 24deg.VISIBLE LEDs... 3mm...14X Red diffused 70deg. 4X 3mm or rect. Yel. diffused 70deg SPECIAL...1X 5mm IR,3X 3mm Clear Phototransistor, 3X 5mm Phototransistor, 1X IR RX module. 2X DIL rect. black PIN Photodiode. SUBSCRIBE TO NEW KITS FROM “OATLEY’S” We are constantly developing many electronic projects, but there is only a limited amount of these that the electronics magazine can publish. If you wish to receive a regular Email and be informed about these projects just send a blank Email with the following text in the subject heading: n e w k i t s - s u b s c r i b e <at> o a t l e y e l e c t r o n i c s . c o m Where possible our Emails will include descriptions, PCB overlays, parts lists and pictures. We will also offer you regular kit specials and where necessary, additional notes and or errata. While you are at it why not subscribe to our Bargain Corner, Just send a blank Email to: bargaincorner-subscribe<at>oatleyelectronics.com In the future you will be able to access this same information at www.newkits.com **NEW**NEW**NEW** but for the moment the ONLY WAY you can do this is by subscribing to the above FUTABA 2 CHANNEL RADIO CONTROL Email address. As an example if you do it now you would be Emailed the following two This item is new in Its original box. projects within the next few weeks. 2ER A high-tech, AM system, ideal for robotics, R/C cars, boats and planes etc. MULTI PURPOSE INVERTER Features inc. Servo Reversing. Includes This modified square wave two S3003 servos, a R122JE receiver, inverter can be used to convert battery holder, power switch and other 12-24V DC to 240V AC, or ] a c c e s s a r i e s . A l l f o r j u s t $ 1 0 0 12-24V DC to 120V AC, or any other voltage Power and voltage (NEW) MULTI FUNCTION BATTERY O/P’s depend on transformer. O/P freq. is adjustable between CHARGER / DISCHARGER: New in original box with instructions. This 50 and 60Hz and a beat indicator unit was designed to charge NI-CD & NI- cct. is included (LED) so you can MH mobile phone batteries of 4.8V, 6.0V easily adjust the freq.. to be the and 7.2V. Operates from 12-24V DC input. same as the mains freq..With one pair of MOSFETS and no additional heat sinks Features include processor control & multi 100W power O/P is possible, 200W with two pairs of MOSFETS and no H/S’s, 400W+ stage charge indicator. By changing the with two pairs of MOSFETS and additional H/S’s, etc…PCB plus all on-board value of one resistor it can charge higher components kit (No transformer):$18...Two additional MOSFETS: $6...US Plugpacks voltages, although a higher voltage with a 30VA transformer: $2.50Ea. We will include notes on how these can be plugpack is required for 9.4V or higher. rewound for 120V O/P (1 needed) or 240V o/p (2 needed) Includes cigarette lighter lead, 12V / 1A DC Coming soon..LOW VOLTAGE 200W LIGHT SHOW..A nice colourful music plugpack & instructions for modifications triggered random and automatic light show, suit a disco or a band..... + MANY MORE for higher voltages. The unit has battery VIDEO CAMERAS charging terminals but the user will have to VIDEO SYNC. STABILISERS make their own adaptor to interface to a Various forms of copy protection are used The output of these cameras below is std battery. The plugpack supplied alone is on video tapes & DVDs, the problem is that video & can be plugged into the "VIDEO worth around $30 retail. Weight is 0.9kg. the changes to the normal signal is that it IN" socket of any Australian std VCR, $29... 15V DC / 1A Plugpack for charging may cause playback problems like the video monitor or TV, or via an RF batteries 9.4V or higher: (ZA0055) $6 If jitters. This device removes the copy Modulator to an Ant. Input. The B/W you ask when ordering you will receive a protection by stripping and reinserting the cameras are Infra Red responsive & can be used in total darkness with IR sync. pulse & thus free 6-pack of batteries. Illumination. cleaning (USED) AUSTRALIAN the picture. MONOCHROME CCD VIDEO CAMERA IEC LEADS: It has been B&W Camera built on a PCB with auto iris. Has 3 pin Australian suggested to us that (0.1 lux). Can be focused sharply down to mains plug these units could be used to copy comm- a few mm(useful for people approximately ercial videos & DVDs but we do not with visual impair1 metre long lead: condone any breach of copyright. This ment). Spec.: (PL2) $2 each item comes as a ready built PCB with a Power req.: 10V to new recycled metal case to suit. Just...$29 12V <at> approx. PELTIER EFFECT DEVICES. 4A T 65deg. Qmax 42W $24 6A T 65deg. Qmax 60W $26 8A T 65deg. Qmax 75W $28 Comes with info to build cooler / heater All 40 X 40mm. PELTIER CONTROLLER KIT this kit is a switch mode design and correctly controls the temperature of peltiers to 10A using a very efficient design. Inc PCB, all on-board components . (k140) $19 NEW 80mm 12V FANS Ideal replacement for computer power supply fans. 12V <at> 0.15A... $4 or 4 for $12 CFL INVERTER KIT our very popular inverter. Very Efficient Driver kit can drive a number of CFL’s from 12vdc$25. QUALITY AUSTRALIAN MADE FEATURE PACKED MINI ALARM SYSTEM CONTROL Features inc. boot release, central locking output, imobiliser output, indicator flash relay. With 2 key-fob transmitter keys. $99 (NEW) 13V- 1A PLUGPACK: $12 4 CHANNEL VIDEO SWITCHER KIT Our kit dosn't use CMOS bilateral switches (4066 etc.) as these chips suffer from crosstalk between chanels (at higher frequencies like those in video signals) and an on resistance that causes impeadance miss-match. This kit can switch manually or sequentially up to 4 audio/video sources. Other features inc. VCR relay output to switch STOP/REC, can be switched with PIR or alarm system inputs Add a security channel to your TV using a VHF modulator, watch TV & flick channels & see who’s at the door or what the Kids are doing. This unit can be switched automatically using PIR units. Kit +PCB+all on-bourd components inc. 18 relays. Less than 1/2 price of most units $50. SERIAL SERVO CONTROLLER KIT: This kit is ideal for robotics kits etc, it controls up to 5 servos via the serial port of your computer. A lot of shareware and support for this kit on the Internet. Features inc. small kit size & hi servo resolution. Kit inc. software, PCB & all onboard components. COMING SOON...around $24 50mA.CCD: 1/3", 30grams: $89, with 92° lens: SUGAR CUBE CMOS B/W CAMERA: (Reviewed EA Sept. 1999) This (16 x 16 x 15mm) black & white video camera includes a pinhole lens with a field of view of 56 x 42 degrees. Resolution is 240 TV lines (288 x 352 pixels), 1/3" CMOS Image Sensor, 2:1 interlace with a shutter speed of 1/60 to 1/60,000. Other features include auto exposure control, backlight compensation, auto gain control. Has an AGC disable pin which can be tied low for outdoor use. It operates from 5V DC and only draws 10mA: (CAM2) $70 GENUINE MAGLITE TORCHES So new it’s hard to tell that they are used, (during the Olympics). The same type as used by police, security guards etc. Complete in original box with booklet, rechargeable batteries, charger and charger clip /wall bracket etc. $150 SAMSUNG LITHIUM BATTERIES As used for a short while during the olympics, 3.6V Li-Ion batteries, as used in Samsung SGH2400 mobile telephones. Standard battery model BTS24G: $7, Extended battery model BTE24G: $11. Lots of capacity in a small package! Priced for experimenters, probably worth 10 times this amount. SOLAR PANELS: Quality SIEMENS brand Polycrystalline cells. Open circuit voltage 5.7V, Short circuit current 0.22A, Peak power 1W <at> 100mW per square cm. 4 panels req. to charge 12V batteries. 160 x 55 x 5mm. Terminated with a 25cm long figure eight cable. $10 ea. or 4 for $36. 2.4GHz SMALL VIDEO/STEREO AUDIO TRANSMITTER KIT: Most transmitters on the market promise 100-200M range & deliver only 50M on open ground with line of site. We tested it in an urban area, in a less than an ideal environment, under power lines, over metal fences & through houses at 200M. At 200M we had a perfect picture, no lines or snow etc. We are working on a Di-pole antenna that should give more than 1 Kilometer range. Easy to build with professionally built modules. Kit available $159 next month. Subscribe to our E-mail list for mor details. SONY UNIVERSAL CAMCORDER BATTERY + CHARGER: Brand new in original packing Less than 1yr. old. 7.2V 1500mAh lithium-ion As commonly used with SONY digital cameras, camcorders, SONY and some other brand products . US made OPREX brand. Charger has an unusual plug that is easy to adapt. Requires power plug-pack (not supplied) 9V 1A (2A peak for 5 minutes)...$39. NEW...always fresh stock 12V / 7AH SEALED LEAD ACID 8 CHANNEL PC CONTROLLED RELAY BATTERY INTERFACE KIT: Ref: Silicon Chip Sept BARGAIN:, 2000. Operates eight relays from a PC 2.6kg, 150 x 65 x parallel port. Kit inc. PCB & all on-board 92mm: (PB6) $25 parts inc. eight relays (2 higher current) with indicating LED's & DB25 connector. Also some simple software We have more used test equipment. on disk. written in Basic we need to clear some to make way for to operate the kit: the next lot. Check out our web site (K164) $40 Great bargains at a fraction of the new A suitable DB25 cost. If it’s not on our web site... ring us male to DB25 female data cable is also available for NEW SHIPMENT WE HAVE TOO MANY ITEMS TO ADVERTISE HERE THE ONLY WAY TO SEE IT ALL IS TO CHECK OUT OUR WEB STIE oatleyelectronics.com www.oatleyelectronics.com Orders: Ph ( 02 ) 9584 3563, Fax 9584 3561, sales<at>oatleyelectronics.com, PO Box 89 Oatley NSW 2223 42  Silicon Chip major cards with ph. & fax orders, Post & Pack typically $7 Prices subject to change without notice ACN 068 740 081 ABN18068 740 081 SC_JLY_01 “DO NOT DISTURB” TELEPHONE TIMER Al Bell invented one of the most useful – and one of the most frustrating – communications devices of all time. What do you do when you don’t want the ’phone to disturb you? T here are times when you simply don’t want to be disturbed by anything, let alone a telephone – especially by that incessant “ring ring… ring ring… ring ring…” Of course, the person at the other end of the line doesn’t know that you are, well, umm, let’s just say you’re otherwise engaged. But you can imagine such times, can’t you? What do you do? Take the phone off the hook? Sure, that works – until a couple of hours/days later you start to wonder why no-one’s ringing you. What you need is either something to remind you to put the phone handset back on the hook – or better still, do it for you so the process is automatic. And that is exactly what the SILICON CHIP “Do Not Disturb” Timer does. Even better, it does it without you by JOHN CLARKE lifting the handset in the first place: you simply set the time period you’re going to be “busy” – whatever that is – and press the start button. The phone then effectively goes off-hook (ie, anyone ringing will get an engaged signal) until the time period is com- plete. The phone is then restored to its “normal” (ie, on-hook and waiting for calls) state. As far as time periods go, you have everything from a sprint to a marathon – 7.5 minutes to a whopping two hours. And if the reason for your not wanting to be disturbed ends prematurely you can hit the “hang up” button at any time. You can even make the offhook time period indefinite by not selecting a time period. If that sort of sounds like you’re defeating the purpose for making the device in the first place, it’s a great little security feature if you don’t want anyone else to use the phone while you’re away from July 2001  43 PLEASE NOTE This Telephone Timer is NOT an Austel-approved devi ce. The penalty for using a no napproved device, if dete cted and subsequent prosecut ion took place, could be a he avy fine, up to $10,000. This almost-larger-than-life photograph shows the completed project. The leads emerging top and bottom plug into the phone and wall socket. It doesn’t matter which way around they go. phone but that is unimportant as far as we are concerned. The timer works by connecting a load across the telephone line to simulate an off-hook condition. This off-hook condition means that there is a nominal 20-25mA drawn from the line. The timer starts and maintains the off-hook condition until the end of the time period or until the “end” switch is pressed. At this time it removes the load across the line, fooling the exchange into believing that the handset has been put back on the phone, readying it for a call. The circuit it – especially if the little box is hid50VDC to around 3-6VDC. The voltage The full circuit for the Do-Notden! drops because of the load provided Disturb Timer is shown in Fig.1. It by the telephone. The voltage drop Speaking of little box, the timer is comprises a 4060 counter IC, a 7555 (or more accurately the significant housed in a small plastic case with a timer IC, a LED, two transistors and a increase in current) is detected at 6P6C telephone socket located at each few diodes, capacitors and resistors. the telephone exchange and so the end. It has a 4-position DIP switch and Diodes D1-D4 provide full wave rectwo tiny pushbutton switches poking tification for the telephone through the box top – one to lines, necessary since the start the timer and one to stop polarity of the line voltage it manually. A LED indicates is indeterminate. y lit faci er tim sh ni Fi d when the phone is off-hook. Power for IC1 & IC2 is an t ar St  us at st k Installation is simple: you oo derived via the rectified f-h of s ow LED indicator sh just unplug the telephone line  telephone line voltage via socket from the phone, plug it  a 220kΩ resistor feeding Powered from phone line ite into the timer, then plug in a zener diode ZD1. This fin de in Four time periods plus modular lead from the timer to  develops a nominal 5.6V the phone. across the supply pins of In case you’re feeling a sense IC1 & IC2, smoothed by telephone is recognised as being of deja-vu, yes, we have described a the 10µF capacitor. off-hook, in anticipation of receiving similar device before – back in July The trigger input to IC2 (pin 2) is either the tones or pulses required to 1992, in fact. But that used an LM3909 initially held high via the 470kΩ redial a number. timer and alas, those devices are no sistor connected to the positive supply If the phone is simply left off-hook more. Hence this new, improved rail, while the threshold input (pin without another number being dialled, model! 6) is initially held low via the 100kΩ the telephone exchange will still recresistor to 0V. This sets the output at How does it work? ognise the telephone as being off-hook pin 3 low. or engaged and prevent incoming When you lift the handset on a NPN transistor Q1 is therefore off calls. After a certain time it will autotele-phone, the voltage across the and so is PNP transistor Q2. The matically send “engaged” tones to the tele-phone line drops from a nominal collector of Q1 is held at the rectified Features 44  Silicon Chip voltage from the phone line via the 2.2kΩ and 1kΩ resistors. This voltage also pulls the reset input of IC1 (pin 12) high via a 1MΩ resistor to reset this counter. Diode D5 prevents this input going above the IC supply rail. Pressing the start switch (S6) pulls the trigger input of IC2 (pin 2) low, setting the output (pin 3) high. Q1 is then switched on via the 10kΩ base resistor. In turn, transistor Q2 is switched on via the base current flow through the 1kΩ resistor and Q1. Transistor Q2 connects two 180Ω resistors in series across the phone line (via the D1-D4 bridge rectifier) to simulate the offhook loading. The voltage across the telephone line now drops to around 6V. Supply is maintained to IC1 and IC2 via diode D10 at the collector of Q2. The indicator LED1 will now be lit via the 1kΩ dropping resistor to indicate the off-hook condition. At the same time, the IC1 reset (pin 12) is released because of the low voltage at Q1’s collector. Components at pins 9, 10 & 11 of IC1 form an oscillator with the internal inverters operating at a nominal 0.88Hz rate. IC1 is a counter – each of its outputs, Q10, Q12, Q13 and Q14, goes high when the IC counts a certain number of pulses from the oscillator. In the case of Q10, it goes high when the count reaches 512 pulses. So if the oscillator is running at 0.88Hz, the output goes high after about 7.5 minutes. Similarly, Q12 counts 2048 pulses, or about 30 minutes, Q13 4096, or about 60 minutes and Q14 8192, or about 120 minutes. In case you were wondering what happened to Q11, 1024 pulses/15 minutes, the answer is that the chip does the count but there are insufficient pins on the IC to bring out all the counter outputs, hence we don’t get 15 minutes! If switch S1 is closed, this high will pull pin 6 of IC2 high to reset it. Pin 3 then goes low, switching off Q1, Q2 and the off-hook loading resistors. As far as the exchange is concerned, the telephone is now back on hook. Fig.1 (right): the circuit diagram shows the simplicity of the design: just one counter IC, one timer IC and a handful of other components. July 2001  45 Here’s the completed PC board out of its case, with the component overlay (Fig.2, right) printed at the same 1:1 scale. What you cannot see here is the switches and LED mounted high off the board to poke through the front panel. For longer times, IC1’s Q12, Q13 & Q14 outputs can also be selected to give timeout periods of thirty minutes, 1 hour or 2 hours respectively. These are chosen with switches S2S4 respectively. Note that if more than one switch is closed, it will be the lowest-time switch which will determine the timeout period, since its output will go high first. The others will be ignored. The “end” switch, S5, can be used to manually (and immediately) end the time period. It pulls IC2’s threshold input (pin 6) high regardless of the outputs of IC1, returning the circuit back to “on-hook”. High voltage transistors are specified to minimise the possibility of breakdown when the phone rings. The ring voltage can be 100Vp-p above the 50VDC line voltage. These transistors are rated at 250V, which will be adequate for preventing breakdown. The terminals for the incoming phone line are labelled as the tip and ring. These names are a throwback to the days when phones actually used 6.5mm phone plugs – the names are used these days to label which of the two wires is nominally “hot”. The two sockets are paralleled, allowing a phone connected to the socket to directly plug into the line, as if the timer were not there. Because the Timer takes the mini-scule amount of power it needs from the telephone line, no battery or other supply is required. This makes it extremely safe. Construction All components for the Timer mount on a PC board coded 12107011 and measuring 50 x 79mm. It all fits inside a plastic case which measures 83 x 54 x 31mm. A 50 x 77mm label is glued to the top of the case. Begin construction by checking the PC board for shorts and possible breaks in the copper tracks. The four corners of the PC board need to be cut to shape Fig.3: same-size artwork for the PC board. At right is the empty case, clearly showing the cutouts required for the phone sockets and the “surgery” done to the internal guides. 46  Silicon Chip to clear the integral pillars in the case. The outline is shown on the copper side of the PC board. You will also need to drill holes for the integral mounting pins on the 6P6C sockets so that they clip in correctly to the PC board. The Altronics type of socket differs slightly to the one sold by Jaycar and so we have provided both hole positions for the mounting pins. The plastic case has integral side clips which will need to be removed with a sharp knife or chisel so that the PC board will slide into the case. Check that the PC board fits into the case without fouling. Insert the resistors in the appropriate place in the PC board using the accompanying resistor colour code table to select the right values. Alternatively, you can use a multimeter to measure the values directly. As the diodes are inserted, make sure the orientation is correct; likewise the transistors, LED, ICs and electrolyt- case and cut out the holes with a sharp knife. Testing Connect the telephone to one socket using a 6P2C (or 6P4C or 6P6C) extension lead and the telephone line into the other socket. You can test the unit by pressing the start switch and checking that the LED lights. You can also measure the voltage between pins 16 & 8 of IC1 and pins 4 and 1 of IC2. This voltage should be be around 5.6V as set by ZD1. Press the finish switch to check that Parts List – "Do Not Disturb" Timer 1 PC board coded 12107011, 50 x 79mm 1 panel label, 50 x 77mm 1 plastic case, 83 x 54 x 31mm 1 4-way DIP switch (S1-S4) 2 snap action PC board momentary closed switches (S5,S6) 2 4-way pin header 8 PC stakes 2 6P6C PC board mounting modular sockets 1 6P2C (or 6P4C or 6P6C) extension lead And here’s how it all goes together inside the case. There’s not much room to spare; in fact you’ll have to cut the corners off the PC board to allow it to fit around the corner pillars in the box. The case side guides also need to be removed. ic capacitors are also polarised. Note that Q1 and Q2 are oriented differently to each other. The electrolytic capacitor requires positioning with the positive lead where indicated. LED1 mounts with its top dome 19mm above the PC board, oriented with the cathode toward the edge of the PC board. The 6P6C sockets can be installed now, followed by the switches. Switches S5 & S6 must be oriented with the “flat” as shown. To be at the correct height, these are mounted on top of PC stakes which are cut down so that the top of the switch is 18mm above the PC board. Switches S1-S4 are mounted on a 2 x 4-way pin header so that its height is sufficient to protrude through the front panel. Place the PC board assembly in position over the case and mark out the cutout positions for the sockets. We cut the box with a fine toothed hacksaw and broke off the piece with pliers. The cutout then was filed to shape. Only cut the hole to the depth of the socket on each end of the box. Test the PC board for fit into the case and adjust any of the cutout sides accordingly. The lid will require a hole for the LED, the two switches and the DIP switch. Use the front panel label as a guide to positioning these. Also the flanges on the lid directly above the sockets will need to be filed flat so that the lid will sit flush on the case. Glue the front panel label to the Semiconductors 1 5mm high brightness red LED (LED1) 1 4060 binary counter (IC1) 1 7555 timer (IC2) 1 BF469 NPN high voltage transistor (Q1) 1 BF470 PNP high voltage transistor (Q2) 4 1N4004 1A 400V diodes (D1D4) 6 1N4148, 1N914 switching diodes (D5-D10) 1 5.6V 1W zener diode (ZD1) Capacitors 1 10µF 16VW PC electrolytic 1 0.47µF MKT polyester (code 474 or 470n) Resistors (0.25W 1%) 2 1MΩ 1 470kΩ 1 220kΩ 2 100kΩ 1 10kΩ 1 2.2kΩ 2 1kΩ 2 180Ω 0.5W July 2001  47 the LED goes off. Set the DIP switch to 7.5 minutes and press start again and check that the LED goes out after about 7-8 minutes. The time is only nominal and will vary depending on component tolerances and the particular 4060 IC. You can make the time periods shorter by changing the 0.47µF capacitor to a smaller value. Longer time periods can be achieved by changing the 0.47µF capacitor to a larger value. A bipolar electrolytic capacitor can be used in place of the MKT type but do not use a standard polarised electrolytic. A final check can be made by lifting the telephone handset and listening for the dial tone. This tone should last for about eight seconds, after which the tone will change to an engaged signal. Now try this with the handset back in place. Press the start switch on the timer and wait for, say, 10-15 seconds. Lift the telephone handset and check if there is engaged signal. If it is engaged you can be sure that the timer has caused the telephone to be off hook. SC S RESISTOR COLOUR CODE 5-Band Code (1%) 4-Band Code (1%) brown   No. Value brown black black yellow ck green brown bla wn bro Ω brown 1M nge ❑ 2 yellow violet black ora yellow brown let vio low yel kΩ wn ❑   1 470 red red black orange bro yellow brown brown nge ora ❑   1 220kΩ red red ck bla brown black black yellow brown wn bro red ❑   2 100kΩ brown ck brown black bla brown black orange brown ❑   1 10kΩ red red black brown brown wn bro red red red kΩ brown ❑   1 2.2 brown black black brown wn bro red ck bla wn bro wn ❑   2 1kΩ brown grey black black bro brown grey brown brown ❑   2 180Ω 48  Silicon Chip Fig.4: 1:1 artwork for the front panel. Use a photocopy as a template to drill the holes required. (This panel and the PC board artwork can also be downloaded from the SILICON CHIP website: www.siliconchip.com.au). SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au Order Form/Tax Invoice Silicon Chip Publications Pty Ltd ABN 49 003 205 490 PRICE GUIDE- Subscriptions YOUR DETAILS (all subscription prices INCLUDE P&P and GST) Your Name________________________________________________________ (PLEASE PRINT) Organisation (if applicable)___________________________________________ Please state month to start. Australia: 1 yr ....................$A69.50 2 yrs .....................$A135 1 yr + binder .....................$A83 2 yrs + 2 binders....$A159 NZ (air): 1 yr .....................$A77 2 yrs .....................$A145 Overseas (air): 1 yr ...........$A125 2 yrs .....................$A250 Address__________________________________________________________ PRICE GUIDE- Other products (all prices INCLUDE GST) __________­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­___________________­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­____________________________________ Postcode_____________ Daytime Phone No. ( )_____________________ Email address (if applicable) ___________________________________________ Method of Payment:  Cheque/Money Order   Bankcard   Visa Card   Master Card Card No. Card expiry date   Signature_____________________________ *BACK ISSUES in stock: 10% discount for 10 or more issues. Australia: $A7.70 ea (including p&p by return mail)     Overseas: $A10 ea (inc p&p by air). *BINDERS: BUY 5 or more and get them postage free.   (Available in Aust. only.) ..........................$A12.95 ea (+$5.50p&p). *SOFTWARE: $7.70 per item (project) plus $3.30 p&p per order within Australia, $5.50 p&p per order elsewhere.       (Most software is available free on www.siliconchip.com.au). *ZOOM EFI TECH SPECIAL               $A8.95 inc p&p Aust; $11.95 inc p&p elsewhere. *COMPUTER OMNIBUS: $A12.50 inc p&p Australia; NZ/Asia/ Pacific $A15.95 inc p&p (air); elsewhere $18.95 inc p&p (air). *ELECTRONICS TESTBENCH: Aust. $A13.20; NZ/Asia/Pacific $A15.95 inc p&p (air); Elsewhere $18.95. (All prices incl. p&p). *SILICON CHIP/JAYCAR WALLCHART:         Unfolded (in mailing tube): $A9.95 including p&p (Australia only) – unfolded version not available elsewhere. Folded: $A5.95 inc p&p within Australia; elsewhere $A10 inc p&p. *BOOKSHOP TITLES: Please refer to current issue of SILICON CHIP for currently available titles and prices as these may vary from month to month. SUBSCRIBERS QUALIFY FOR 10% DISCOUNT ON ALL SILICON CHIP PRODUCTS AND SERVICES* *except subscriptions/renewals and Internet access Item Price Qty Item Description P&P if extra Total Price Spec i SUB al Offer SCR IBE & COM PUTE GET R OM FO N Aust R FREE! IBUS ralia Only* Total $A TO PLACE YOUR ORDER Phone (02) 9979 5644 9am-5pm Mon-Fri Please have your credit card details ready OR Fax this form to (02) 9979 6503 with your credit card details 24 hours 7 days a week OR Mail this form, with your cheque/money order, to: Silicon Chip Publications Pty Ltd, PO Box 139, Collaroy, NSW, Australia 2097 * Special offer applies while stocks last. 07-01 MAILBAG Nokia Datasuite less than magic Your Mobile Magic article in the March 2001 issue was very interesting reading, if not a bit too kind to the likes of Nokia. I purchased the Datasuite 2.0 a few years ago and found it to be OK but overpriced. When I upgraded my laptop computer and reinstated it, I found out that infrared communications did not work any more, for the reasons you point out in the article. Hoping for a quick fix from Nokia proved elusive and when Datasu­ite 3.0 came out, I thought I would upgrade and thereby solve my problems. Not so. Not only was it impossible to get the upgrade from Nokia but they kept referring me to dealers who did not stock it. They all wanted to sell me the new version complete, not the upgrade. You would think a large company like Nokia would have a website where you can just download these things using your credit card. I finally did find it on the web but not from Nokia or one of their dealers. It was a freebie and I did not have the slight­est feeling of guilt downloading it, under the circumstances. Needless to say, it did not solve my problem and I am very happy that I did not pay for it. The point I am trying to make is that a multi-billion dollar company cannot make a small piece of comms software work. How ridiculous. And they keep advertising the product as being infrared-capable. Sure, if you like to run 6-year old software on an ancient laptop, it works fine. Horst Leykam, via email. Historical articles needed Am I correct in writing that SILICON CHIP is now the only Australian magazine catering for the electronics enthusiast? If so, then congratulations! I am very pleased that I can still find a magazine that has interesting articles and projects to build. Keep them coming. However I think there is something 58  Silicon Chip missing: historical articles describing electronics from the past; similar to the articles written by the late Neville Williams. There must be a lot more stories to be told and a lot of information to be col­lected before it is lost forever. In the past I have enjoyed the historical articles in SILI­CON CHIP such as the series on “The Evolution of Electric Rail­ways” and “The Story of Electrical Energy”. Any historical arti­cle is wonderful reading. Is there any more of this sort of material coming? They would ‘round’ SILICON CHIP up quite nicely. What do others think? Duncan Graham, Hamilton, New Zealand. Licence required for cable installers I read with interest your comments on electrical wiring. You may also be interested to know that the ACA (Australian Communications Authority) now stipulates that installers of alarm or computer cable (where it is fixed) require a licence. The “reason” behind this brain-wave is that these devices can be connected to the telecommunication network and licensing install­ ers will stop them from possibly causing damage to their phone network, even though modems and alarm panels have inbuilt isola­ tion (and have done so for probably more than 10 years). The upside to this is that there are now a number of train­ing programs available in the cabling areas. The downside (apart from the revenue collecting side) is that if Joe Citizen decided to run his own home computer network (cable behind the plaster and putting sockets in the wall) between his office and bedroom, he would be breaking the law unless he has a licence (assuming one of his computers is connected to the phone system). The ACA “Cabling Provide Rules” book states that “cabling without a current registration or a current licence is a criminal offence punishable on conviction by fine”. You can apply for a transitional registration which enables you to achieve ACA’s competency requirements by 2 October 2003. So now you need a licence to run wires. Makes you wonder what you will need a licence for next! Phillip Star, via email. More information can be found at: www.aca.gov.au/standards/cabling www.standards.com.au (look up CCM.PACKAGE. Communications Cabling Package cost $165.00). Australian GPS software available I really enjoyed your article on GPS for a PC in the April 2001 issue. I thought I would drop you a line on an Australian GPS software pack. It was written by Des Newman in Queensland with a trial package available at www.oziexplorer.com This package allows the user to run moving maps scanned into a PC. Maps can be calibrated and used with almost all the features available on the most expensive GPS units. Des provides a special price for Australian users who wish to upgrade to the registered program. This is by far the best program I have used for GPS and is always under review and up­grade. Doug Braidwood, via email. Electrical engineers have little chance of a licence In regard to Mr Hoolhorst’s letter on pages 12 & 13 of the May 2001 issue, he is wrong in point 9 where he says that in Australia there is no way to avoid the 4-year apprenticeship. This is totally untrue. Even minimal research, like one or two phone calls, would have shown that there are many ways to become a fully licensed electrician. I’m actually quite surprised that SILICON CHIP did not know this. You can do a TAFE course “Electrical Wiring For Engineers”, which allows you to sit an exam for an electrical contractors license. You are also eligible for this if you have done a TAFE associate Diploma or Diploma in Electrical Engineering. After seeing the nightmare work of home handymen and wir­ing, I believe that unless you have a license, you should be heavily fined for even touching an electrical terminal. I’ve seen so-called handymen using speaker cable to run power, not using double-insulated cable, using unprotected cable outdoors, using the wrong coloured wires (I kid you not, Green/ Yellow used as active), and making double-ended plug/plug extension leads. The point is, this voltage is deadly. It only takes one idiot to wire something wrong in a house for it to kill people. You may think you know what you’re doing but a little knowledge is dangerous. Darryl Lewis, Australian Broadcasting Corporation, Enterprise Application Developer, Information Technology Services, Ultimo, NSW. Comment: firstly, NSW IS THE ONLY STATE that has a structured path for electrical engineers and associate engineers to become licensed electrical contractors. Secondly, the Electrical Wiring course for engineers has been superseded by a new course, “Certificate III in Electrical Wiring”. Why the new course? Many electrical engineers and asso­ciate engineers who properly completed the old course were then FIRMLY REFUSED LICENCES by the electrician dominated “assessment committee” and the resultant indignation forced the introduction of the new system where you have to be assessed and accepted as suitable BEFORE they allow you to do the course. MOST electrical engineers and associate engineers simply don’t qualify! An electrical engineer has to have had VERY CLOSE day to day involvement with the work of electrical installations of various types for AT LEAST TWO YEARS and MUST DEMONSTRATE A GENUINE NEED FOR A CONTRACTORS LICENCE before that engineer has any chance of making the grade with the electricians who make up the overwhelm­ing majority of the members of the “assessment committee”. A very important point here is that design experience is simply nowhere near enough, regardless of the type and period of that design experience! For others with lower qualifications it is much worse. None of the various electronics qualifications, not even the Associate Diploma in Electronics Engineering, qualifies you to apply to do the “Certificate III in Electrical Wiring” and then gain a li­cense. Only the Associate Diploma in Electrical Engineering is a suitable qualification enabling you to apply. Secondly, an associate electrical engineer must have proof of not two (which is already too long) but AT LEAST FOUR YEARS of VERY CLOSE day to day involvement with the work of electrical installations of various types and again, MUST DEMONSTRATE A GENUINE NEED FOR A CONTRACTORS LICENCE before that associate engineer has any chance of gaining approval to do the “Certifi­cate III in Electrical Wiring”. Help wanted on curve tracer I bought an old Leader LTC-905 transistor/Fet curve tracer with probes and leads at the local markets for a few dollars and although it works fine, I don’t know how to interpret the plots it makes on my scope when testing transistors. Perhaps someone out there either has a manual for it, or knows how to interpret the scope display. john-richardson<at>bigpond.com Transformer needed for Tektronix scope I have a Tektronix 422/r422 with a defunct high voltage transformer (Pt No 120-0378-02). I am hoping there is someone out there who can tell me were I can get a replacement unit from. I would be very grateful and would pay all the required costs. Mick Jezzard (mjezzard<at>senet.com.au) 3 Comley St, Brighton, SA 5048. Engineers and technicians are competent to do electrical work I am commenting as an electrician about non-electrical personnel doing their own wiring. Firstly, I cannot understand why an electrical engineer is not permitted to do his own wiring, espe­ cially since he designs installations and therefore must know more than the average electrician. Silly rules like these must cause anger and frustration. Electronics technicians also work on far more complicated circuitry than the average electrician. But I do believe the general philosophy and work practices are quite different for these two disciplines. A technician may find much of an electri­cian’s wiring rough but providing the electrician runs cables beside beams, not over them, uses correct cable sizes and junction boxes and follows earthing requirements, the installation is safe. I read the example where the electrician wired to the line side of a main switch; one can only call that electrician a goose. Some electricians also fail to check the condition of the MEN. I would have thought that to be his first priority as a bad or non-existent MEN is the most common cause of the fatalities we read about in the newspapers from time to time. Tradesmen from all different trades know if a “trady” has done the work and so it is with an electrician. That is not to say I believe a technician cannot do a better job than me on an install. I also find it ridiculous that an electrician should electrically check a piece of equipment a technician manufac­tured. But I also believe an electrician has skills that a technician does not have, even though the circuitry is rudimentary. I can understand the frustration of technicians; surely they should be allowed to cross-skill (it wasn’t too long ago that an electrician could not crossskill into refrigeration even though refrigeration involves lots of electrical work) but I do believe they need to be taught the philosophy of this trade. But please keep wiring out of the hands of the general public. Let’s not have such a closed shop but I believe some training is essential. John, via email. July 2001  59 The Simplest Digital Alarm Clock Ever PIC-TOC PIC-TOC What has less than twenty components and can make sure you wake up in time for work, school, that early morning golf game . . . It’s an alarm clock, of course. But it’s not just any alarm clock . . . It’s a PIC TOC! Design by Michael Moore ­Words by Ross Tester N ow before you say “Oh no, not another clock project…” have a closer look at this one. It has just a handful of components yet offers features such as a melody alarm, high-brightness readout and a seconds display. It’s designed to operate from a plugpack supply but is just as happy running from a car or caravan battery (in fact, anything from about 9-17V DC). So if you’re travelling a lot and want a reliable alarm clock for the ’van or motorhome, this one is ideal. And you’ll be able to knock it up in less than an hour. Everything mounts on one small PC board and the “case”, if you can call it that, is simply a cheap, tiny photo frame from your local bargain store (about two bucks’ worth!). And because it’s based on a PIC micro, we’ve called it the PIC TOC. Oh, come on, it’s not that bad! PIC TOC. TIC TOC. Geddit? The circuit As you might expect, to be as simple as what it is the clock uses just a single micro – in this case, the ubiquitous 60  Silicon Chip PIC16F84. All that is attached to the PIC is a 4MHz crystal-controlled oscillator (so it’s nice and accurate), the push-button setting switches, a buzzer and four low current, high intensity 7-segment LED displays (via suitable resistors). Apart from the power supply, that’s all there is to the circuit. The secret is, of course, in the software – FEATURES: build!  Cheap and easy to  4 very bright digits  Push-button setting  Melody alarm  AM/PM indication in this case, the PIC is loaded with a program called alexcloc.hex. And just in case you’re wondering, Alex is the little girl this clock was first built for. So now you know! PortA 0-3 (RA0-RA3) of the PIC serves as the multiplexer, sourcing one of four seven-segment common anode LEDs in turn. These LEDs re- quire just 3mA per segment and give a nice bright display straight from the PIC without the added complexity of driver or multiplexer circuitry. 3mA times 8 segments (don’t forget the decimal points!) equals 24mA – just below the 30mA sourcing limit of a PIC16F84 I/O port. The fifth PortA (RA4) is used to drive the audio output, which goes to a piezo buzzer. RA4 is an “open drain” output – that is, it will only go low, not high. Because of this, some buzzers may require a resistor in parallel (say 1.1kΩ to keep it all nice and simple!) but in the case of the buzzer specified, no resistor is necessary. Provision is made for such a resistor on the PC board should it be needed. PortB feeds the individual LED segments – when one of the PortB I/O pins (RB0-RB7) goes low, the segment turns on. Obviously, Port A controls on which digit the segment gets turned on. PortA multiplexer outputs which are not having a turn as a source are kept in the high impedance input mode. This is more for experimental reasons than anything to do with the The PICTOC is housed in one of the cheapest cases we’ve ever used: a $2.00 photoframe! But it sure looks the part . . . design/software presented. By putting them into high impedance mode, it would be possible to add on additional common cathode 7-segment LEDs in parallel with the existing four common anode 7-segment LEDs, or add a set of switches. Port A can act as a Tristate 4-output pin multiplexer, giving each of 4 pins a turn at being a sink, a source, or off. Incidentally, I had planned originally to add two extra 7-segment displays to the clock (ie, seconds) but decided not to do so because the extra LEDs would have reduced the brightness. There is nothing to stop this circuit being adopted to become a frequency counter, tachometer or variable sweep generator with appropriate software – and in this case, brightness is probably less important. Four switches are connected to the highest digit’s PortA pin (RA0). Every hundred milliseconds or so, PortB (which normally drives the LED segments) is switched to input mode and RA0 goes low. If one of the switches is being pressed the relevant PortB input will be pulled low. The software detects which switch is being pressed. Normally, these switches would short out the corresponding LED segment when pressed unless they were connected via a diode opposite in polarity to the LED segment. But in this case – a 12-hour clock – only three segments are used for the highest digit’s display. So the four switches are connected to the unused segments, keeping the component count to a minimum. The program We are not going to attempt to print the program listing for alexcloc.hex – Here’s another view of the photo-frame “case”, this time sans bits. You cannot even see the glass – but it’s there. We would have preferred a piece of red acrylic but didn’t have any on hand. . . apart from taking a lot of pages, who in their right mind would type it out when you can download it, free of charge, from the SILICON CHIP website: www.siliconchip.com.au? This program can be loaded into your PIC using one of the PIC Programmers described earlier this year (January and March 2001 issues). Alternately, it is expected that some kit suppliers will have available pre-programmed PICs. There is only one hardware timer in the PIC16F84, and this is needed to keep a precise count for the clock. So it cannot be used to produce audio output – a software timer is used to regulate the audio tone instead. All the main duties such as monitoring the hardware timer, keeping track of the time, multiplexing the digits and so on, are broken down into identical length subroutines. The main program counts these subroutines to time the period of the note that is being played and can therefore generate a note at the correct frequency. The main program actually generates a tone continuously but the tone is inaudible unless a key is pressed July 2001  61 or the alarm goes off . The method is not exact but is exact enough – the ear cannot detect anything amiss! Construction The clock is housed in a tiny picture frame. OK, so it’s not quite in – it’s more ON the picture frame, surrounded by part of a plastic box. All components – switches included – mount on a small PC board, coded 04207011. Most components mount in the normal way on the top of the board. The exceptions are the four time-setting switches, the main filter capacitor and the piezo buzzer, all of which solder to the back (copper side) of the board. Start by cutting and soldering the various links on the PC board. Some of these are very close together and should therefore be insulated. Also, room must be left for the 7-segment displays – some links are hard against the displays. One link, on the right side, actually goes around the end display so ensure enough length is left to achieve this. Next, solder in the four LED displays. Note that two of these mount the opposite way to the other two (this gets the “colon” between the hours and minutes. Note where the labels on the displays are and place them the same way as shown on the component overlay (Fig. 2). Be careful soldering the pins – there isn’t a great deal of room between them (the same comments apply to the PIC Fig.1: yes, this is the complete clock circuit. There’s not much in it, is there! Just a PIC, oscillator, piezo buzzer and four setting switches plus power supply regulator make up the entire project. 62  Silicon Chip Here’s the DSE Utility Case after we “operated” on it to make it shorter than the maker intended! At 10mm high and with no “bottom”, it’s perfect for the switches to poke through as seen in a later photograph. The “stand” came from the original frame. Fig.2: here’s how the components go on the PC board. The four push buttons, 100µF electrolytic capacitor and piezo buzzer are mounted on the underside. socket and the resistor array. Make sure the PIC socket goes in the right way around (cutout closest to the edge of the board). If your eyes aren’t as good as they once were (and perhaps even if they still are!) check for solder bridges with a powerful magnifying glass. The PC board is designed for either an 8 x 1.1kΩ resistor array or eight individual 1.1kΩ resistors. We prefer the individual resistor approach because arrays are not only harder to find, they’re more expensive. Complete the top side construction by soldering in the polarity protection diode, regulator, crystal and various capacitors. Crystals and ceramic capacitors aren’t polarized; electrolytic capacitors are. Note that the 10µF capacitor lays on its side. Now turn the board over for soldering on the underside components. Three of the switches – black, green and yellow – mount the same way with their flat side facing to the left when you look at the copper side of the board with the switches at the bottom. The fourth switch, the red one, mounts with its flat side facing upwards – see the component overlay again for a clearer picture. You’re going to need a very fine point on your soldering iron to solder the switch pins to the tracks underneath. The 100µF electrolytic capacitor and piezo buzzer solder on the underside of the PC board. The capacitor (lying on its side) is easy because you have access to the legs. The buzzer is not so easy. The way we did it was to apply solder to the copper pads, poke the There are minor differences between this photo and the overlay at left (it’s of an earlier prototype) but nevertheless will give you a good idea of where the bits go! piezo’s leads through and then heat the leads from the top side. This melted the solder underneath and the joint was made. But it’s not a method you’ll find in the rules according to Hoyle (or whoever wrote the soldering rules!). Remember too that the piezo is polarised – it won’t work the wrong way around. Finally, solder in the wires to the DC supply socket. The socket should be connected with the positive to the center, which is the convention for plugpacks more often than not – until some idiot manufacturer decides his plugpacks are going to have negative to the middle! There’s not much room in the case to mount the DC socket – we managed to squeeze it in one side after making sure all the terminals were well covered with insulation to prvent shorting to the back of the PC board. The protection diode will prevent any catastrophes if you do use a wrong-polarity plugpack – but of course, the clock won’t work. You’ll need to find a plugpack with the right polarity – anything capable of seven or more volts (up to about 17V) and a couple of hundred milliamps will be fine. Carefully plug the pre-programmed PIC into its socket – the right way around and without bending any pins – and your clock is now electrically complete, ready for testing and then mounting in its case. Testing Apply power via the DC socket. The display should read 1:23, with a dot up in the left corner (indicating PM). And you should be greeted with a “ta-da” tone. Press the black (mode) button – it cycles the display through its various modes. Press once and the display changes from hours/minutes to seconds (preceded by a high-pitched tone), press it again it changes from seconds to alarm (preceded by a short melody) and press it one more time to switch The purpose of this pic is two-fold: (a) to show the way we (carefully!!) soldered the four pushbutton switches to the back of the PC board (with the piezo buzzer and electrolytic capacitor somewhat hidden behind) and (b) to highlight the fact that two of the 7-segment displays are reversed with respect to their mates. July 2001  63 At left is the reverse (copper) side of the PC board (again, an earlier prototype than the final board whose same-size pattern is shown above). As you can see, this board also needed a bit of surgery due to over-etched tracks – something you need to check your board for. back to clock mode again (preceded by a low-pitched tone). If all this is OK, move on to checking the alarm function with the red button. Pressing this not only turns the alarm on (and of course off), it also lights the bottom right dot LED to show it is in alarm mode. Finally, the green and yellow buttons are used to change the two left and two right digits respectively, incrementing the digits in both clock Parts List – PIC TOC 1 PC board, 50 x 75mm, coded 04207011 1 Plastic utility case, 57 x 82 x 33mm (DSE Cat H-2923) 1 Miniature wooden photo frame (with glass), 107 x 81 x 17mm with   “photo” cutout 51 x 76 x 10mm (available from bargain stores) 1 2.5mm DC power socket 1 mini PC board mounting normally open single-pole pushbutton  switch, red (Jaycar SP-0720 or similar) 1 mini PC board mounting normally open single-pole pushbutton  switch, yellow (Jaycar SP-0722 or similar) 1 mini PC board mounting normally open single-pole pushbutton  switch, green (Jaycar SP-0724 or similar) 1 mini PC board mounting normally open single-pole pushbutton  switch, black (Jaycar SP-0721 or similar) 1 piezo transducer, PC board mounting (Jaycar AB-3459 or similar) 1 4MHz crystal 1 200mm length of insulated tinned copper wire (for links) 1 100mm length mini figure-8 (or two strands of rainbow cable) Semiconductors 4 HDSPH101 high intensity, low current, 7-segment common anode  LED displays (Farnell Electronics 324-723) 1 PIC16F84, pre-programmed with alexcloc.asm (downloadable from www.siliconchip.com.au) 1 78L05 low power 5V regulator (TO-92 package) 1 1N4004 silicon power diode Capacitors 1 100µF 25VW PCB-mounting electrolytic 1 10µF 16VW PCB-mounting electrolytic 1 0.1µF ceramic or polyester (code 104 or 100n) 2 22pF ceramic (code 22 or 22p) Resistors (0.25W, 1%) 8 1.1kΩ (brown brown red brown or brown brown black brown brown) * * PC board will also accept an 8 x 1.1kΩ resistor array 64  Silicon Chip and alarm modes. In seconds mode the yellow button increments the minutes and the green button resets the seconds to zero. If all this appears to be working as it should, you only have two more tests to make. One is that the clock does actually work – set the time and ensure the digits change – and the other is that the alarm actually works – set the alarm time for, say, two minutes ahead and then wait that two minutes to ensure that Beethoven’s Pastoral Symphony greets you! Once you’re happy it all checks out OK, it’s time to place the clock in its unique case. The “case” As we mentioned before, the clock mounts inside a cheap (two dollar) miniature photo-frame which we obtained from our local bargain store. The frame we used measures 107 x 81mm and is about 17mm deep but the more important dimension is the cut-out for the “picture”. In our frame it was 76 x 51mm – you’d almost think the PC board at 75 x 50mm was designed to fit, wouldn’t you? Our frame had a small piece of glass, against which you’d normally place the picture. Instead, we placed the PC board – the LEDs contacting the glass. To be honest, we would have preferred a piece of 2mm-thick red acrylic in place of the glass – it would hide everything inside and accentuate the LEDs. But time beat us so we stuck with the glass. Now, what holds the PC board in place? You can’t use the normal backing supplied but don’t throw it out – we’re going to use the support stand attached to it. Instead, we used a Utility Box from Dick Smith Electronics. Actually, that’s a lie: we used 1/3 of a Utility Box from Dick Smith Electronics. The box we used (H-2923) has cable entries and mounting points emerging from each end. We didn’t need the cable entries but the mounting points we did! The box is 57 wide, 82 deep and 33mm high. The width and depth are fine, the height is far too much. So we removed the lid and carefully measured a line 12mm down from the case top, cut this with a hacksaw then smoothed it on a sheet of sandpaper (ie, rubbing it on the sandpaper, not the other way around). The photo shows you what we ended up with. In the lid, we drilled 10mm holes for each of the four pushbutton switches and the DC socket (see photo above right). And remember that support stand we mentioned a moment ago? This was also fastened to the lid to allow And it’s finally assembled. We see a cut-down instrument case which holds the “works” onto the photo-frame. The four push- buttons set time and alarm. What you cannot see in this photo is the side-mounted socket for DC power input. the clock to stand up vertically (again, refer to the photographs). The PC board is not glued or screwed to the case – it doesn’t need to be. Just pop the four push-buttons through their holes. (That’s the reason the holes are slightly oversize – it allows for a little bit of error.) When finished, we simply placed the lid onto our piece of case and screwed the whole lot to the wooden frame Winning Gold . . . . . .After the Games EX OLYMPIC GENUINE MAG LITE TORCHES Made in USA, complete with 240V battery charger kit and in car battery charger kit. As used by Police, Navy & RTA using some 20mm self-tappers. (Drill a pilot hole in the frame first to avoid splitting). If necessary, some foam rubber can be slipped in between the lid and the PC board to keep the LEDs hard against the glass in front. And that’s it. Plug in power, set the clock and settle back and enjoy! Now, what can we do with 2/3 of a SC utility case without a lid? HURRY! This is your LAST CHANCE to grab some of the equipment left over from the Sydney 2000 Olympic Games at never-to-be-repeated prices! CALL NOW! PH: (02) 9879 6782 FAX: (02) 9879 6993 180 ea $ EX OLYMPIC SECURITY DURACELL 9 VOLT BATTERIES Brand new (expiry dates 2004) Boxed lots of 48 1 00 $ 79 ea $ 80 ea EX OLYMPIC TOA MEGAPHONES Complete with shoulder harness and alkaline batteries ALL PRICE INCLUDS E GST ® DON’T MISS OUT! ® Registered Trade Mark Australian Video Systems July 2001  65  NiCads   NiMHs   SLAs   LiIONs   Bike batteries   Car batteries. . . IT'S THE ONLY BATTERY CHARGER YOU WILL EVER NEED, EVER AGAIN! Fast   Universal Power Charger . Part 2 By JOHN CLARKE For power tools, camcorders, R/C equipment and car batteries Last month we introduced our new, improved Universal Fast Charger for a huge range of batteries. Here’s the nitty gritty: how to build it! 66  S ilicon hip 66  S iliconCC hip I t’s arguably the only “high capacity” fast battery charger you’ll ever need – ever again! It will easily handle all the batteries you have in your power tools – it will even charge your car or motor bike battery! And while it won’t handle low capacity “AA” cells it can charge their big brothers – 1200mAh and above – along with “C” and “D” types of 1200mAh or more. For a more detailed list, see the panel at right or refer to the full description of operation in last month’s SILICON CHIP. Construction The SILICON CHIP Universal Fast Battery Charger is housed in a plastic instrument case measuring 257 x 190 x 85mm while the components are mounted on a PC board coded Main Features  Fast charges Nicad, NiMH, LiION, SLA and Lea d-Acid batteries  Suitable for 1.2V, 2.4 V, 3.6V, 4.8V, 6V, 7.2V, 8.4 V, 9.6V, 12V & 14.4V bat from 1.2Ah to 4.2Ah plus teries LiION 3.6V, 7.2V & 14.4V  Charges either 6V or 12V SLA batteries from 1.2 Ah to 4Ah  Charges 6V or 12V Lead-Acid batteries of any cap acity above 1.2Ah  Includes a discharge r for Nicad batteries  Top-off charging at end of fast charge plus pul sed trickle charge for Nic  Voltage limited charge ad & NiMH for SLA & Lead-Acid bat teries  Voltage drop & tem perature rise (dT/dt) full charge detection for Nicad  Under and over-temp & NiMH erature cutout for battery  Over temperature cut out for charger  Short circuit battery protection  Time-out protection  Fuse protection  Multi-LED charge ind icators This photo shows the completed project, giving a good idea of where the various components are located. Probably the most difficult part is winding the inductor (bottom right) but even this is a snack! July 2001  67 Figs 1&2 show both sides of the PC board, with the relevant section of the under-side shown below. LEGEND: = PC BOARD PIN NP = NON-POLARISED (BIPOLAR) CAPACITOR K A K A 56k K K 12k LED4 2.2k Q2 BC337 K 10mF 100V 2.2k 0.5W D1 MUR1550 68W ZD1 4.7k 14106011 and measuring 121 x 173mm. If IC1 is the surface mount or “ T” version, a small satellite PC board, coded 14302982 and measuring 29 x 16mm is also required . Transformer T1 is mounted sideways onto the rear metal panel as shown in the photographs. Underneath its mounting position on the case are several integral ribs and bushes (mounting pillars). These must be removed to allow the transformer to sit flat. The easiest way to remove the ribs is with a sharp chisel (careful!!) while the bushes are easily cut out with a large, sharp drill bit. The main PC board fits over four integral bushes in the base of the case, secured with self-tapping screws. Other bushes (under the board) may get in the way of the PC board or components – again, these can be easily removed with a large drill. Begin construction by checking the PC board against the published pattern. There should not be any shorts between, or breaks in, the tracks. If there are, repair these as necessary. 68  Silicon Chip 10mF 100V 0.1W 5W 0.1W 5W 1000mF IC3 4020 Q5 BC337 D5 1N914 1N 4148 0.1mF 10mF 16V 1 220k Q1 TIP147 22k IC2 4093 NP 10W 3.3mF 1N 4148 D4 680W 1 VR1 250k A BC548 LED5 D6 1N914 15k Q4 A 33k 1k D3 1N 4148 10k ZD2 D2 MUR1550 1M L1 1k 1W 33k 1mF 18k 25V A 18k 1k 1W 33k 100mF 20k LED3 100k 10mF 35V 27k 0.18mF 10k 100k LED2 820pF IC1 TEA1102 100k Q2 TIP142 27k 12k TPGND 100mF 16V 1 33k LED1 3.3k 30k PC stakes are used wherever connections need to be made to the PC board. These are soldered in first, in the positions indicated. Doing these first also acts as a guide to the positions of the links and resistors, which can be soldered in next. Use the accompanying table as a guide to working out which resistor goes where – or measure them with a digital multi-meter. Note that some resistors are mounted as a parallel combination: one is inserted as normal from the component side of the PC board while the second (shown in red in Fig. 2 at right) is soldered between the pigtails of the first resistor on the underside of the PC board. When inserting the smaller diodes and zeners, take care with their orientation and be sure to place each type in its correct place. Solder in the ICs and transistors, also taking care to orient them as shown. As mentioned before, IC1 may be supplied as a surface-mount type. If so, it must first be soldered onto the small carrier PC board, which in turn is connected to the main PC board with wire links or pin headers. Parts List – Universal Fast Battery Charger II 1 PC board coded 14106011, 121 x 173mm 1 PC board coded 14302982, 29 x 16mm (required for T version of IC1) 1 front panel label 244 x 75mm 1 plastic instrument case 250 x 190 x 80mm 1 aluminium rear panel to suit above case 1 heatsink 109 x 75 x 33mm (DSE H-3460 or equivalent) 1 18V 6A mains transformer (T1) (DSE M-2000 or equivalent) 1 ETD29/16/10 transformer assembly with 3C85 cores (L1) (Philips 2 x 4312 020 37502 cores, 1 x 4322 021 34381 bobbin, 2 x 4322 021 34371 clips) 1 NTC thermistor (DSE R-1797) (NTC1) 2 3AG panel-mount safety fuse holders (F1,F2) 1 630mA slow-blow 3AG fuse 1 7A fast-blow 3AG fuse 1 SPST Neon illuminated mains rocker switch (S1) 1 SPDT centre-off toggle switch (S2) 1 2-pole, 4-position rotary switch (S3) 1 4-pole, 3-position rotary switch (S4) 1 single pole, 10-position (1P10W) rotary switch (S5) 1 80°C thermal cutout (TH1) 1 momentary normally off push button switch (S6) 1 black 4mm heavy duty banana panel socket 1 red 4mm heavy duty banana panel socket 1 black 2mm micro banana panel socket 1 red 2mm micro banana panel socket 1 black 4mm heavy duty banana plug 1 red 4mm heavy duty banana plug 1 black 2mm micro banana plug 1 red 2mm micro banana plug 5 M4 screws x 10mm 6 M4 nuts and star washers 4 M3 screws x 10mm and nuts 1 M3 screw x 25mm and nut 4 self-tapping screws to mount PC board 4 insulating bushes for TO-220 and TO-218 packages 2 TO-218 insulating washers 2 TO-220 insulating washers 31 PC stakes 1 7.5A mains cord with plug 1 mains cord grip grommet 2 1mm spacers 10 x 5mm to gap L1 1 600mm length of red hookup wire 1 600mm length of green hookup wire 1 600mm length of blue hookup wire 1 600mm length of yellow hookup wire 1 600mm length of black hookup wire 1 300mm length of red heavy-duty hookup wire 1 300mm length of black heavy-duty hookup wire 1 150mm length of 0.8mm tinned copper wire 1 2m length of 1mm enamelled copper wire 1 55mm length of 15mm diameter heatshrink tubing 1 50mm length of 25mm diameter heatshrink tubing 10 small cable ties 2 solder lugs for earth terminals 2 10-way single in-line pin headers (if IC1 is surface mount “T” version) 5 5mm LED bezels Semiconductors 1 TEA1102 or TEA1102T fast charge IC (IC1) 1 4093 quad Schmitt NAND gate (IC2) 1 4020 binary divider (IC3) 1 TIP147 PNP power Darlington transistor (Q1) 1 TIP142 NPN power Darlington transistor (Q2) 2 BC337 NPN transistors (Q3,Q5) 1 BC548 NPN transistor (Q4) 2 MUR1550, BYW81P/200 fast recovery diodes (D1, D2) 1 1N4004 1A diode (D3) 3 1N914 or 1N4148 diodes (D4-D6) 1 35A 400V bridge rectifier (BR1) 1 12V 1W zener diode (ZD1) 1 11V 400mW zener diode (ZD2) 5 5mm red LEDs (LED1-LED5) Capacitors 1 1000µF 63VW PC electrolytic 1 100µF 25VW PC electrolytic 1 100µF 16VW PC electrolytic 2 10µF 16VW PC electrolytic 2 10µF 100VW MKT polyester (Philips 373 series) 1 3.3µF bipolar electrolytic 1 1µF 16VW PC electrolytic 1 0.18µF MKT polyester 1 0.1µF MKT polyester 1 820pF MKT polyester or ceramic Resistors (0.25W 1%) 1 1MΩ 1 330kΩ 1 150kΩ 5 100kΩ 1 68kΩ 4 33kΩ 2 27kΩ 1 22kΩ 2 18kΩ 1 15kΩ 1 10kΩ 1 4.7kΩ 1 2.2kΩ 0.5W 2 1kΩ 1W 1 680Ω 1 68Ω 2 0.1Ω 5W 3 220kΩ 2 82kΩ 1 30kΩ 1 20kΩ 2 12kΩ 1 3.3kΩ 1 1kΩ 1 10Ω Miscellaneous Heatsink compound, solder, etc. July 2001  69 should be written on each component. The electrolytic capacitors must be oriented with the correct polarity (with the exception of the 3.3µF bipolar type which can be mounted either way). Now install the trimpot. In similar fashion to the power transistors, the LEDs solder to the PC board and also emerge through the front panel. To allow this, the LEDs are inserted through the board with just enough length poking through to allow soldering. The LEDs are then bent over over Fig.3: the detail of the inductor winding. It so that they can protrude through has two windings but both go on as one. the holes in the panel. We don’t have to remind you to make sure The power transistors and power they’re the right way around, do diodes solder to the PC board but are we? No, we didn’t think so. . . also secured to the rear panel and The inductor (L1) is wound with heatsink. They are oriented with the two lengths of 1mm enamelled copper metal flange towards the edge of the wire, wound in “bifilar” mode – the PC board and are positioned above two lengths are wound as one with the board with sufficient lead length each turn of the winding actually being to allow them to reach their mounting two turns side-by-side, one from each holes on the rear of the case. length of wire. Capacitors can be soldered in next. Fig.3 explains this method of windThe accompanying capacitor table ing. First, if the wire is supplied as a shows the various codes, one of which two-metre length (as specified in the parts list) cut it exactly in half. Now let’s see . . . each length will be, uhh, um, too hard . . . Next remove the insulation from one end of each of the two lengths of wire and terminate (solder) the two ends onto two pins on the underside of the transformer bobbin. The actual pins used doesn’t matter since they are connected together on the PC board anyway. Now wind on the two windings of 20 turns by holding both lengths of wire between your thumb and forefinger and winding them on as one (ie, side-by-side). Once wound, cut the excess wires off, strip the insulation from their ends and terminate the wires onto the pins on the opposite side of the former. Again, the actual pins used are not important. Insert one core in place and secure with a clip. Now place the 1mm spacers on the two faces of the inserted core and place the second core in position, securing it with the clips supplied. Insert this inductor assembly into the appropriate place on the PC board and solder in place. An angled view of the rear of the case, particularly showing the method of mounting the power transistors and diode, the thermistor (with the red wires), bridge rectifier (block in the middle), transformer and mains wiring. Note that all mains wiring must be insulated with heatshrink tubing, as shown on the fuseholder at right of picture. 70  Silicon Chip That pretty much completes the PC board assembly – all that's left now is to mount the board (and everything else) inside the case. Assembly Place the PC board into the case (on its four bushes) and mark out the positions for the power transistor and diode mounting holes on the metal rear panel (a fine-tipped felt pen is ideal). Remove the rear panel from the case (it slides out) and drill out these holes plus two holes for the cord grip grommet and fuseholder in the position shown on the wiring diagram. 4mm holes are required for the transformer mounting and the earth termination plus the bridge rectifier mounting position above D1, along with the holes to mount the thermal switch TH1. All holes should be deburred with a larger drill, especially for the semiconductors to prevent punch- Capacitor Codes          Value 0.18uF 0.1uF 820pF IEC 180n 100n 820p EIA 184 104 821 Resistor Colour Codes – Universal Fast Charger    No. Value 4-Band Code (1%) 5-Band Code (1%)  1 1MΩ brown black green brown brown black black yellow brown  1 330kΩ orange orange yellow brown orange orange black orange brown  3 220kΩ red red yellow brown red red black orange brown  1 150kΩ brown green yellow brown brown green black orange brown  5 100kΩ brown black yellow brown brown black black orange brown  2 82kΩ grey red orange brown grey red black red brown  1 68kΩ blue grey orange brown blue grey black red brown  4 33kΩ orange orange orange brown orange orange black red brown  1 30kΩ orange black orange brown orange black black red brown  2 27kΩ red violet orange brown red violet black red brown  1 22kΩ red red orange brown red red black red brown  1 20kΩ red black orange brown red black black red brown  2 18kΩ brown grey orange brown brown grey black red brown  1 15kΩ brown green orange brown brown green black red brown  2 12kΩ brown red orange brown brown red black red brown  1 10kΩ brown black orange brown brown black black red brown  1 4.7kΩ yellow violet red brown yellow violet black brown brown  1 3.3kΩ orange orange red brown orange orange black brown brown  1 2.2kΩ red red red brown red red black brown brown  3 1kΩ brown black red brown brown black black brown brown  1 680Ω blue grey brown brown blue grey black black brown  1 68Ω blue grey black brown blue grey black gold brown  1 10Ω brown black black brown brown black black gold brown Here’s a similar view to the facing page, this time looking from rear to front and showing the switch wiring. Follow the wiring diagram and photos and you should have no difficulties. Note that the front panel is plastic, providing insulation from the mains. If a metal panel is used, it must be securely earthed back to the main earth point on the rear panel. July 2001  71 USAGE NOTES: (1) This charger is not suitable for charging cells and batteries with capacities below 1.2AH and voltages below 6V. AA and AAA Nicad and NiMH cells should not be connected to this charger as the "No Batt" LED will light due to the cell voltage rising above 2V with initial charging. However, the charger will charge a 6V AA Nicad battery pack successfully. (2) When charging older cells either singly or in series it is important to ensure that their contacts are clean to prevent voltage drops across these connections. High resistance connections will prevent the charger from operating correctly as it will detect a high voltage per cell and simply indicate "no Battery". In addition the connecting leads from the charger to the cell or cells must be rated at 7.5A or more and be no longer than necessary to prevent voltage drops. Fig.4: the complete wiring diagram of the charger, shown with the two panels laid out and flat. The earth lug (top of drawing) should ideally be a crimped type, not a solder type. The front panel should be the plastic one supplied with the case. If a metal panel is used it must be earthed back to the main earth point on the rear panel. The thermistor mounted on its flying leads. Connection to the front panel is via miniature banana plugs. through of the insulating washers and to ensure a flat contact to the heatsink. Place the heatsink against the rear panel and mark out the hole positions for drilling into the heatsink. Note that you must line up the heatsink so that the screws for Q1, Q2 D1, D2, bridge rectifier and thermistor will pass through the heatsink between the heatsink fins. Drill out and deburr these holes. Attach the PC board to the case with self-tapping screws. Apply a smear of heatsink compound to the flat face of the heatsink and secure the transistors and diodes to the rear panel and heatsink with a screw, nut, insulating washer and insulating bush. If you use a mica washer apply a smear of heatsink compound to the Fig.5: Cross-section through the heatsink, panel, semiconductor and its mounting hardware. It’s vital that the power transistors and diode are insulated from the rear panel. mating surfaces before assembly. (Silicone-impregnated glass fibre washers, much more common these days, do not require heatsink compound.) Check that the metal tabs of the devices are indeed isolated from the case by measuring the resistance to the case with a multimeter – it should show open circuit. Apply a smear of heatsink compound on the face of the rectifier (BR1) before securing it to the rear panel. It is not necessary to insulate the rectifier case from the rear panel. Pass the mains cord through its cord-grip grommet and secure the grommet into its rear panel hole. Also attach the fuseholder and secure the transformer with 4mm screws, star washers and nuts. Attach the earth wire (green/yellow stripe) to the solder lug (or preferably a crimp lug) and secure to the rear panel with a screw, star washer and nut. The front panel can now be drilled out to accept the switches, terminals and fuseholder. We used bezels to mount the LEDs – they hide a multitude of sins, especially holes that don’t quite line up! A photocopy of the front panel artwork (Fig. 6) can be used as a template for drilling. Attach the rear label in place after drilling and cut out the holes with a sharp hobby knife. The shafts of the rotary switches need to be cut down with a hacksaw. Many rotary switches supplied these days are universal – the number of positions required need to be set. If this is the case, you will need to set S5 as a 10-position, S3 as a 4-position, and S4 as 3-position type. Repeated from last month, this photo shows the mounting of the heatsink, transformer, mains lead and fuseholder. The screws in the heatsink go right through the panel to hold the power transistors and diode in place. 74  Silicon Chip July 2001  75 Fig.7: same-size drilling template for the rear panel. Fig 6: same-size artwork for the front panel. Use a photocopy as a drilling template. This label must be paper or plastic, not metal, to ensure insulation integrity is maintained between the wiring and the user. If a metal panel is substituted for the plastic panel ensure it is properly earthed. This is done by removing the locking collar from beneath the star washer and nut and rotating the switch fully anticlockwise. Then reinsert the locking washer into position 10 for S5, position 3 for S4 and position 4 for S3. Now assemble all the front panel components. Follow the wiring diagram, using coloured hookup wire. The mains wiring must be done using mains-rated wire, with the terminals for the fuse and power switch sheathed (insulated) with heatshrink tubing. Use heavy duty wiring for the connections between the rectifier and PC board, the thermal switch and to the output terminals and fuse F2. Tidy up the wiring with cable ties and insert the front panel into it slots in the case with the LEDs protruding through their bezels. You will need to make up some heavy-duty leads to connect from the output terminals to a battery, using heavy-duty banana plugs and large alligator clips. The thermistor, too, requires a connecting lead. This can be light-duty figure-8 or twisted hookup wire, terminated in miniature banana plugs. The thermistor leads themselves should be sheathed in heatshrink tubing where they solder to the connection lead. Testing Check your work carefully to ensure correctly placed components, orientation of the polarised parts and wiring. Test that the earth termination connects to the rear panel case by measuring the resistance between the earth pin on the mains plug and the case. It should be zero ohms (or very close). Now apply power and measure the voltage between the TP GND PC stake and pin 12 on IC1. You should measure about 12VDC. Check that pin 14 and pin 16 of IC2 and IC3 are at 12V. Switch S3 to the NiCd & NiMH position and check that the “no battery” LED lights. Connect the NTC thermistor and check that the voltage at pin 8 of IC1 is at about 2V when the temperature is around 25°C. Adjust VR1 for this voltage. If you heat up the thermistor slightly by gripping tightly between your finger and thumb the voltage should drop. If the temperature rises then it 76  Silicon Chip Figs.8 & 9: full-size artwork for the main PC board and the optional daughter board, required only for a surface-mount IC1. is either a very hot day and your body temperature is lower than that of the air (unlikely during winter!) or you have the wrong type of thermistor (eg, a PTC instead of NTC). When charging a battery make sure you select the correct battery type and voltage on the front panel switches. Also set the timer for the closest timeout period for the particular battery capacity. If you are charging a lead-acid battery then the timeout setting does not matter. You may wish to check the charge current using an RMS meter or a dig- ital oscilloscope which reads RMS. If a standard multimeter (ie, not a true RMS type) is used, you can expect the reading across the two 0.1Ω resistors in parallel to be about 200mV. An RMS reading should show about 300mV which is equivalent to 6A. Note that the heatsink and Q1 will run hot on fast charge and so the charger should be provided with sufficient ventilation to prevent the thermal SC cutout operating. COMPUTER TIPS: Making Windows Work For You Backing Up Your Email If you rely on your email system, you’ll probably have a sizeable address book that you use regularly. Losing your address book, not to mention all those messages, could be a real pain, right? But how do you back them up? by PETER SMITH Microsoft’s Outlook Express stores all address book data in .WAB (Windows Address Book) files. Each person that logs into a particular computer has his or her own address book. For example, if you log in as “George”, your address book would be named George.WAB. You could just copy all .WAB files to back up all address books but there is a snag. With version 5.x of Outlook Express, Microsoft introduced a new feature call “Identities”, which enables multiple accounts to co-exist on the same PC using a single .WAB file. To successfully back up a specific “identities” address book, you need to log in as that identity and perform an address book export. You can then back up the exported file for safekeep- Fig.1: the Options dialog box for Outlook Express. ing. All message folders and associated files can be backed up directly – but Windows ME and DOS Remember MS-DOS? If you’ve upgraded to Windows ME, you’ll notice that Microsoft have given it the old heave-ho. In other words, you can’t boot to a DOS prompt or run those real-mode games or utilities that you used to be able to with earlier versions of Windows. You can’t even create a DOS startup disk! Despair not. If you really can’t do without the “>” prompt, then check out the following web sites that offer free patches and utilities to correct this obvious oversight by Microsoft! www.overclockers.com.au/techstuff/a_dos_me/ www.geocities.com/mfd4life_2000/ members.tripod.co.uk/bootdiskmaker/boot3.htm Fig.2: the Store Location dialog box. how do you find out where they’re stored? Open Outlook Express and on the Tools menu, click Options. Click the Maintenance tab and then click on the Store Folder button. The Store Location dialog box displays the directory in question (Fig.2). For step-by-step backup instructions, check out the following web pages: http://support.microsoft.com/support/kb/articles/q188/8/54.asp (Outlook Express 4) http://support.microsoft.com/support/kb/articles/q270/6/70.asp (Outlook Express 5) HyperTerminal Update Do you use HyperTerminal? If so, you may have noticed that it has a number of annoying bugs. Hyper­Terminal is supplied free with Windows 95/98, Me and NT, and is part of the standard Windows installation. Consider upgrading to version 6.1, available free to download from the Hilgraeve web site located at www.hilgraeve.com As well as bug fixes, this latest version includes a couple of extra features as well. For Windows 2000 users, the HyperTerminal update is included in the recently released Service Pack 2. Making A Quick Exit From Windows 98 – Just Click Once Here’s an addition to your Windows 95/98 desktop that you will use every day. It allows you to exit Windows at warp speed, using just one mouse click instead of the usual three! Right-click on any blank space on the desktop. Choose New -> Shortcut and enter the following in the Command line box exactly as it appears below: C:\WINDOWS\RUNDLL32.EXE C:\WINDOWS\SYSTEM\USER.EXE,ExitWindows Note that there is no space after the comma and case must be as shown. Click the Next button and you will be prompted to select a name for the shortcut. Enter whatever you like, then click Finish. Make sure all applications are closed before double-clicking on your new shortcut! July 2001  77 SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.altronics.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.altronics.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.altronics.com.au A high performance colour scope in a shoebox Here’s a machine that many engineers and technicians would kill for: a four channel 100MHz scope with a VGA colour liquid crystal display, inbuilt disk drive, parallel printer port and a host of measurement facilities and it all fits into a case the size of a shoebox! Review by LEO SIMPSON Tektronix TDS 3014 four channel colour oscilloscope July 2001  81 F or a number of years now we have been using a Tektronix TDS 360 1GS/s 200MHz digital scope for most of our measurements. You would have seen the scope traces published regularly in the pages of SILICON CHIP. We have really liked that scope for its combination of performance and features and at the time of purchase, we considered it the best overall value for our application. Tektronix have moved on quite a way since producing the TDS 320/340/360 series and their low-end scopes are now compact instruments featuring liquid crystal displays. In view of this, we decided to have a look at what is perhaps their benchmark instrument in the TDS 3000 colour range, the model TDS 3014. This is a four-channel scope with a 100MHz bandwidth and a maximum sampling rate of 1.25 Gigasamples/second. Our review sample was also fitted with the TDS 3TRG advanced trigger module and the TDS 3FFT (Fast Fourier Transform) module to give measurements in the frequency domain (ie, spectrum analysis). So all up, this is a high performance combination in a pretty compact package. In fact, if you are familiar with the typical digital oscilloscope of just a few years ago, you will know that they are fairly bulky instruments. For example, the TDS 360 model referred to above has an overall depth of about 470mm, not including the handle. By contrast, the model TDS 3014 has roughly the same width and height (just a little more) but its depth is only 145mm. In other words, it is about the size of a shoebox (albeit a pretty expensive one!) In regard to weight, the model TDS 360 tips the scales at about 7kg while the TDS 3014 is half that, at about 3.5kg, making it highly portable. So not only is the new model half the weight, it takes up only a fraction of the bench space required for the old model. In most applications, that is a very important advantage. Digital phosphor oscilloscope As far as Tektronix is concerned, the big feature of the TDS 3000 series is the colour VGA liquid crystal display and you have to agree that compared to the conventional green monochrome CRT, the colour screen is a big advance, particularly when you have up to four (or more) traces on screen. Each trace has a different colour and with the addition of the Math function trace, you can have up to five different coloured traces on screen: Channel 1, yellow; Channel 2, cyan (blue); Channel 3, magenta (pinky/purple); Channel 4, green; and Math, red. In addition you can also display up to four REF waveforms and these are all shown in monochrome (ie, white). To see how busy the screen can be with the maximum number of traces displayed, have a look at Fig.1. Trying to examine a mono screen with all those signals would be impossible. Mind you, you can select monochrome for all traces instead of colour but why anyone would want to do that escapes us. Maybe if you are colour blind? Some readers may be wondering why Tektronix refer to this range of scopes as DPOs which stands for “Digital Phosphor Oscilloscope”. This refers to the Tektronix method of intensity modulation which imitates the screen phosphor of an analog CRT (cathode ray tube) oscilloscope. Areas where the signal is concentrated (as in an amplitude-modulated 82  Silicon Chip Fig.1: This shows the capability of the VGA (640 x 480 pixels) display to show a lot of waveforms on the screen. In this case we have the four channels, a MATH waveform (in red) and four REF waveforms (in white). Fig.2: For easy setup of scope parameters, go to the QuickMenu. This displays and allows you set Vertical, Acquire, Cursors and Trigger parameters. Fig.3: This is another subset of the QuickMenu options, showing the Video triggering options. (Yes, we know those aren’t video signals). Fig.4: This screen has four measurements selected, for different channels. If you try to select more measurements, the scope will throw up a message on the screen telling you to remove a measurement before you can select another. RF signal) appear the brightest and areas where the signal is moving fastest (ie, rising and falling edges of pulses) appear dimmer. While we don’t particularly like the Tektronix DPO label for this technology, it is a big advance on previous digital scopes and gives a more realistic (ie, analog) picture of the signal you are measuring. Having said that, you can vary the degree of intensity modulation on the waveforms by using the “Waveform Intensity” knob on the righthand side of the control panel. Also, the REF and Math waveforms are constant brightness; ie, no intensity modulation is used. You should be able to see this effect in Fig.1. Before we leave the subject of the colour screen, we thought that it would have been nice if the probes had matching colour rings to identify them. On our review machine, they were supplied with red, white, orange and black rings. Why not make them available in the four colours displayed on the screen traces? This would also match the channel selector buttons on the control panel. I contacted Tektronix and suggested it. Guess what: current production models have the probe rings matching the channel colours. Ease of use Fig.5: Once you clear the measurement menu off the screen (by pushing the Menu Off button) the four measurements are then displayed to the right of the screen and do not clutter the waveforms. Fig.6: Normal MATH functions in the TDS 3000 series allow you to add, subtract, multiply or divide any two channel signals together, or any combination of the input channels with any of four stored reference signals. This screen shows the MATHematics trace in red, as the sum of channels 1 and 3. Two things we particularly liked about the TDS 360 were the ease of use, in getting a waveform on the screen and then varying all the display parameters, and then selecting a whole range of measurements of which four can be displayed on the screen at any time. The TDS 3000 series is even better in this respect, particularly in respect to its “QuickMenu” button. As before, you can connect any or all of the four channels to signals and press the “Autoset” button to set the timebase and vertical sensitivity on each channel to display a useable trace. At the same time, the scope triggering selects the lowest active channel as the source, usually Channel 1. From there you can go in and change the vertical, horizontal (timebase) and trigger settings and a bunch of other features to get the scope display you want. But doing all of that would normally require quite a few button presses. On the TDS 3000 series, you can bypass a lot of those steps by pressing the QuickMenu button; it displays a whole lot of scope settings, as shown in Fig.2. Note that the vertical sensitivity for all active channels is always shown at the bottom of the screen and again, the colours match the traces. Also shown are the timebase setting, the channel selected for triggering (Channel 1, in this case), the trigger slope, trigger level and trigger time reference. QuickMenu information is displayed below and to the right of the screen graticule. At the bottom are the vertical input conditions for the selected channel (Channel 3, in this case), the Acquire settings and Cursors (Off, Vertical or Horizontal). Trigger settings are shown to the right of the screen, in five separate boxes: Trigger type (edge or video), Trigger mode, Trigger source (channel 1, 2, 3 or 4, Alternate or AC line), Trigger Coupling (DC, Noise reject, HF reject or LF reject) and Trigger slope. Note that each one of the displayed QuickMenu settings can be changed by pushing the adjacent button (below or to the right of the screen; you do not have to go back to the individual menus to make these changes. July 2001  83 Note also that if you select Video triggering from the QuickMenu display, it all changes, as shown in Fig.3. You then have the choice of Video standard (NTSC, PAL or SECAM) and field or line triggering (Even, Odd or All fields or All lines). Yes, we know that Fig.3 doesn’t show video waveforms but we got lazy for this screen grab. By the way, the waveforms shown in Figs.1, 2 and 3 are from the Li’l Pulser switchmode train controller published in the February 2001 issue of SILICON CHIP. I should note that on our review sample, if you press the Trigger menu button, you have more options apart from Edge and Video triggering: Logic and Pulse triggering and all the associated parameters. These are the additional features of the Advanced Triggering Module. For example, if you go for pulse triggering, you can select width, runt and slew rate, with the latter set to ECL, TTL or adjustable high and low thresholds. That’s pretty comprehensive. Measurements Where the Tektronix TDS 3000 series really shine is in the Measurement department. Not only is there a host of different measurements but they do not interfere with the waveform display. Some other scopes we have seen throw up cursors whenever you select an amplitude or frequency-related measurement and those cursors ride on the waveform while ever the measurement is displayed annoying. In all, 21 different measurements are available, including Frequency, Period, Rise & Fall Time, Positive & Negative Duty Cycle, Positive & Negative Overshoot, Peak-Peak, Amplitude, Mean, RMS and so on. Only four measurements can be displayed at a time and they can all relate to one selected channel or to all four channels (but still only four measurements can be displayed). As you select each measurement for a designated channel it is displayed on the righthand side of the screen. Fig.4 shows a screen with four measurements selected, for different channels. If you try to select more measurements, the scope will throw up a message on the screen telling you to remove a measurement before you can select another. A good feature is that once you clear the measurement menu off the screen (by pushing the Menu Off button) the four measurements are then displayed to the right of the screen and do not clutter the waveforms. Fig.5 shows the result. This is particularly important if you want to save the screen waveforms to a monochrome printer – you do not want measurements printing over waveforms. Again, notice that the displayed measurements are in the same colours as the designated channel. This is just one of the little niceties that you get with a colour display. We mentioned printing the waveforms and the TDS 3000 series come standard with a parallel printer port and a whole bunch of inbuilt generic printer drivers. Normally though, connecting a printer is too much of a hassle and most users would probably prefer to save the printer files to the floppy disk drive for printing later on. Of course, we take the scope files and include them in our published articles. But just how do you go through the process? Well, it ain’t intuitive, that’s for sure! And it is not at all obvious even after reading the relevant sections of the manual, under the heading “Save/Recall”. We did manage to do it, as is evidenced by the waveforms in this article. What you don’t do is to push the Save/Recall 84  Silicon Chip Fig.7: This screen shows the FFT trace (red) when channel ? is selected for analysis. You can set the vertical scale to linear or dbV RMS and the FFT window to Hamming, Blackman-Harris, Hanning or Rectangular. Fig.8: This NTSC video waveform is a good illustration of the intensity modulation of the VGA display. This is every bit as good as the equivalent screen on an analog scope with a conventional CRT. Fig.9: This is the same video signal as in Fig.8 but with triggering on all lines of the signal. Maths functions Fig.10: Winding the timebase up to 1µs/div lets you view the colour burst of the video signal in Fig.9. button. This will certainly read the directory of any disk that happens to be in the drive but you will go red in the face trying to save screen grabs to it. You can save and recall waveforms, either to internal memory or the disk but that is entirely another matter. No, what you have to do is press the Utility button and then cycle through the screen menus to bring up Hard Copy. You then press Port Centronics and change it to Port File (Aaah!). But that’s not the end of the story. You then have to choose the Hard Copy format and you have 16 options, ranging from mono and colour inkjet printers, laser or dot matrix printers and files in formats such as TIFF, EPS, BMP, PCX, IMG and so on. And you can also choose Landscape or Portrait orientation for your printouts. OK, so we chose TIFF format. What to do then? It had us really tricked. Finally, the light went on and I pressed the Printer button on the lefthand side of the screen and the disk drive started whirring merrily away. As Homer Simpson often exclaims, “Doh!”. I suppose it should have been obvious but it wasn’t. Of course, as with the previous model TDS 360, once you set these things up, you seldom have any reason to change them and it can be really hard to figure out how you did it. And finally, as an embarrassing footnote to my detective work, I then found the disk save procedure a couple of nights later, clearly outlined on page 3-21 of the instruction manual, under the heading “Hard Copy”. Yes, I know, I know: read the instruction manual! Normal MATH functions in the TDS 3000 series allow you to add, subtract, multiply or divide any two channel signals together, or any combination of the input channels with any of four stored reference signals. Fig.6 shows the MATHematics trace in red, as the sum of channels 1 and 3. Our sample machine also had the FFT module fitted so you can do an FFT (Fast Fourier Transform) analysis on any of the four channels or any of the stored REF signals. Typically, the bandwidth of the FFT is limited by the timebase setting. The same comment applies to the sampling rate. The maximum sampling rate is only available for timebase speeds of 1µs/div and above. Fig.7 shows the FFT trace (red) when channel 1 is selected for analysis. You can set the vertical scale to linear or dbV RMS and the FFT window to Hamming, Blackman-Harris, Hanning or Rectangular. Video waveforms Finally, a demonstration of the TDS 3014’s performance on video waveforms. Fig.8 shows an NTSC video waveform and is a good illustration of the intensity modulation of the VGA display. Fig.9 shows its performance when triggering on all lines of the signal. The triggering is effective enough to easily examine the waveform but not quite stable enough to allow reliable measurements such as frequency. To do that, you would need the line triggering feature in the optional video triggering module. Fig.10 shows the timebase wound up to 1µs/div to display the colour burst. Summary As with any review of a complex digital oscilloscope it is just not possible to do full justice to all its features in a few pages. However, having used it for a few weeks, we can see why it is one of the best selling Tektronix scopes ever. Its combination of compact size, light weight, colour display and 100MHz 4-channel performance plus exellent measurement facilities make it a very attractive package to any engineer or technician. For further information on the TDS 3000 series you can check the website at www.tektronix.com or phone (02) 9888 0100. Pricing on the review TDS 3014, complete with four passive 10:1 probes, the advanced trigger and FFT modules SC is $9882 including GST. At the rear of the TDS 3014 is the standard parallel port and a compartment for the optional battery pack. When this option is not used, the compartment is handy for storing a couple of probes. July 2001  85 product review . . . PrismSound dScope Series III Audio Test System The dScope Series III is a complete audio system which works in both the digital and analog domains. Its inbuilt generator produces a wide range of analog and digital test signals and its analyser then produces a performance analysis of the equipment under test. T he big advance of the dScope is that it is completely under the control of your PC, using either Windows 2000 or Windows 98. In fact, clicking on the dScope shortcut even turns the machine on! Our previous experience with complete audio analysers has been largely confined to our own Audio Precision test set although we are briefly familiar with the notable Tektronix 700 audio analyser. Our Audio Precision machine is DOS-controlled although Windows upgrades are available. However, the dScope is the most completely Windows-controlled audio test set we have come across. Another big advantage over the esteemed Audio Precision test set is that the dScope does not require a large custom card to be installed in the PC which for the AP set means that it is permanently tethered to one particular PC. Instead, the dScope links to any PC, laptop or whatever, via a USB (Universal Serial Bus) cable. That means you 86  Silicon Chip can use it with any machine that has the software loaded. Hardware required is a Pentium 200 (or above) PC or laptop with 24MB of free memory, running Windows 98 or 2000, CD-ROM drive and USB port. The software comes on CD-ROM and auto-runs as soon as you slot it into the drive (provided you have auto-play enabled). Once the software is loaded, you can start the machine just by clicking on the desktop short-cut. The machine itself is quite compact and has seven XLR sockets on the front panel, for the Generator and Analyser inputs and outputs. As well, there are BNC sockets for unbalanced inputs and outputs and for monitor (external oscilloscope, AC millivoltmeter, etc) outputs. Optical (TOS) sockets are also provided for the digital inputs and outputs. There is also a headphone socket and volume control, for monitoring the signals. . . . by Leo Simpson can be easily varied from the various windows. We have taken some screen grabs to demonstrate some of the operations. Apart from being entirely controlled under Windows (the only panel control is the headphone volume knob), the Prism dScope is a highly specced audio test set. Its analog audio generator operates from 1Hz to 86kHz. THD + noise over the range from 20Hz to 20kHz (for sinewaves) is -105dB (<.0006%). Output waveforms can be sinewave, square, ramp, burst, white noise, pink noise, MLS, pulse, twin-tone and arbitrary. The digital generator can produce the same waveforms as the analog with frequency range from 1Hz to 96kHz (fs/2). Dither is applied as white TPDF or plain truncation. DC resolution is 48 bits. A large range of digital carriers are supported, including AES3(XLR), S/PDIF and TOS (optical). On the analyser side, the analog amplitude range Setting up the dScope is done under Windows. A separate window is opened for each function. In this case there are six windows displayed, with the active window having a green title bar. While the software is claimed to be intuitive (the same claim is made for virtually all Windows software), we found that there is quite a learning curve as you build familiarity with all the operating features. Most of these are brought into play by the toolbar at the top of the screen or in the various windows brought up as you select a feature or operating mode. These toolbars are quite complex and we found all the little symbols anything but intuitive at first – “inscrutable” would be a better word. However, perseverance pays off and you soon begin to appreciate how all the parameters and operating modes dScope can display Generator and Analyser waveforms and again, the timebase and other settings are controlled by opening separate windows. dScope can operate in both the frequency and time domain, as indicated by this screen which has a window for the time domain detector. The drops down menu shows some of the measurements which can be made. is large, ranging from the residual noise of 1.1µV up to the maximum peak input of 159V RMS (-116dBu to +46dBu; ie, referred to 1mW into 600Ω). Residual THD + noise for 20Hz to 20kHz is -108dB (.0004%). As you would expect, both the analog and digital analysers fully complement the analog and digital generators and the whole system can fully check both channels of a stereo system, driving both channels simultaneously, in balanced or unbalanced mode. All in all, the Prism dScope Series III is a very impressive instrument. Further technical information can be obtained from the PrismSound website at www. prismsound.com The Australian distributor for PrismSound products is Control Devices, 1/150 William Street, East Sydney, NSW SC 2011. Phone (02) 9356 1943. July 2001  87 PRODUCT SHOWCASE Branded PC cards from DSE There are literally thousands of PC upgrade cards available out there. But do you know what you’re getting? For the most part, they’re either unbranded or carry a very obscure brand. Trying to buy another card the same as one you like can be daunting, if not impossible! Dick Smith Electronics have decided to change that by introducing a range of name-branded cards. Prominent in the USA, the “Dolphin” cards are new to the Australian market and are exclusive to DSE. They range from standard parallel and serial ISA and PCI cards through network cards to advanced USB and Firewire PCI cards. While intended for self-installation, DSE can also supply local installer details or do it for you at a DSE Power-House ‘Computer Upgrade Centre’. Contact: Dick Smith Electronics 2 Davidson St, Chullora NSW 2190 Phone: (02) 9642 9100 Fax (02) 9642 9153 Website: www.dse.com.au SMD R-G-B point-source LEDs A new line of point-source redgreen-blue surface-mount LED pixels have been released by Lumex (USA). These appear as full-colour point sources to the human eye and are able to generate any mix of the three primary colours. They’re idea for high-end indoor and outdoor signage, full-colour video displays or anywhere multi-colour lights are needed in strips or clusters. There are three individually-ad- dressable chips (R,G,B) in each SMD package. Built-in reflectors and/ or lenses combine the output to what appears to be a pointsource pixel, even at just 10cm away. Contact: Lumex Inc 290 E Helen Rd, Palatine, Il 60067 USA Phone: (0011) 1 847 2790 Website: www.lumex.com Double-insulated DMM from Jaycar Jaycar Electronics has released a new, auto-ranging Digital Multimeter that is designed to IEC1010 specifications. The unit is double insulated and can be used on 600V category III and 1000V category II installations at voltages up to 750AC and 1000V DC (relative to earth). The meter, Cat QM-1540, has an attractive modern styling and features Auto Power Off, Data Hold, Relative Measurement, Frequency and an audible overload warning as well as the normal Voltage, Current, Resistance and Capacitance ranges. Recommended retail price is $89.95 For more information, contact your nearest Jaycar store or visit the Jaycar website. Contact: Jaycar Electronics 100 Silverwater Rd, Silverwater NSW 2128 Phone: (02) 9741 8555 Fax (02) 9741 8500 Website: www.jaycar.com.au FREE SPEAKER PROJECT Authorised Distributors in Australia & New Zealand DOWNLOADS visit www.mass.com.au PLUS all the data, info and price lists you need on world-famous VIFA and ScanSpeak drivers: Build-your-own or buy ready-made speakers. sales<at>mass.com.au Ph: (08) 9434 4030 Fax: (08) 9434 9423 88  Silicon Chip ONICSHOWCASELECTRON ite web s o k c e h f C ore in for m Programmable arms, walkers and mobiles from robot-Oz “Hexapod 1” BASIC Stamps® and ® Muscle Wire www.robotoz.com.au Ph: (08) 9370 3456 NEW! HC-5 hi-res Vid eo Distribution Amplifier DVS5 Video & Audio Distribution Amplifier Fax: (08) 9370 2323 VGS2 Graphics Splitter MicroZed Computers GENUINE STAMP PRODUCTS FROM Five identical Video and Stereo outputs plus h/phone & monitor out. S-Video & Composite versions available. Professional quality. For broadcast, audiovisual and film industries. Wide bandwidth, high output and unconditional stability with hum-cancelling circuitry, front-panel video gain and cable eq adjustments. 240V AC, 120V AC or 24V DC High resolution 1in/2out VGA splitter. Comes with 1.5m HQ cable and 12V supply. Custom-length HQ VGA cables also available. Check our NEW website for latest prices and MONTHLY SPECIALS www.questronix.com.au Email: questav<at>questronix.com.au Video Processors, Colour Correctors, Stabilisers, TBC’s, Converters, etc. QUESTRONIX All mail: PO Box 548, Wahroonga NSW 2076 Ph (02) 9477 3596 Fax (02) 9477 3681 Visitors by appointment only Scott Edwards Electronics microEngineering Labs & others Easy to learn, easy to use, sophisticated CPU based controllers & peripherals. PO Box 634, ARMIDALE 2350 (296 Cook’s Rd) Ph (02) 6772 2777 – may time out to Mobile 0409 036 775 Fax (02) 6772 8987 http://www.microzed.com.au Most Credit Cards OK TOROIDAL POWER TRANSFORMERS  Manufactured in Australia  Comprehensive data available HARBUCH ELECTRONICS Pty Ltd 9/40 Leighton Pl. HORNSBY NSW 2077 Ph (02) 9476-5854 Fx (02) 9476-3231 EasyJack turns a power point into a phone socket With computer users needing closeby phone line sockets for Internet access, a new product released by Smart Connect is sure to find a ready market. It’s a device which allows phone signals to be sent around the home or office via existing 240V wiring. Called EasyJack, the Austel-approved system has a “base unit” which is plugged into any existing phone outlet and 240V outlet. An extension unit can then be plugged into any power outlet and any phone device, whether an actual phone, a modem, fax machine, etc, can simply be plugged into that extension unit. Suggested retail price will be around $239, which is similar to the retail price of the unit in the USA. Sold under various well-known brands, it has been on the US market for four years and has been popular with both home and business users. It is being marketed to retailers in Australia by Brilliant Marketing. Contact: Brilliant Marketing Phone: (02) 9715 5966 July 2001  89 VINTAGE RADIO By RODNEY CHAMPNESS, VK3UG How to repair Bakelite cabinets Up till now, restoring a valve radio set with a broken Bakelite cabinet was regarded by most people as a lost cause. Bakelite is a very brittle material and is hard to glue satisfac­torily. Right? Wrong! Read how it can be done. What an absolute shame it is when the inside of the set is in good condition but the cabinet is broken. How many sets are there that cannot be restored due to a broken case? How many have been consigned to the rubbish heap because what was once a beautiful cabinet is now a pile of broken junk? The value of a set with a broken cabinet (or dial scale) is almost nil. Wouldn’t it be wonderful if the cabinet from a Bakelite radio could be repaired and made to look like it did when it was first sold? Too right – you say – but it can’t. Well I thought so too – they were beyond redemption if extensively damaged. However, a fellow member of the local vintage radio club, Ralph Robertson, has shown that even badly broken cabinets can be effectively repaired. Each collector cum restorer has his or her particular area(s) of expertise and one of Ralph’s is the restoration of Bakelite cabinets. Many fine examples of his art are displayed in his collection. For the purposes of this story, I applied his methods to an STC A-141 mantle set with a badly broken cabinet. This is the same make and model as the set featured in last month’s article. In fact, if you have a good look at the photos in last month’s article, you will see that it is the same set! We’ll bet that few readers noticed that the cabinet had been extensively repaired. Repairing the cabinet Photo 1: normally, you would not consider restoring this sorry looking mess. The cabinet looks well beyond redemption. 90  Silicon Chip I’ve taken nine photos to demonstrate the stages of this repair and as you can see, it is a real wreck to begin with. In fact, the cabinet would normally have been consigned to the garbage bin. Basically the cabinet was in two halves, with the grille in several pieces and unfortunately some pieces were missing. Photos 1 & 2 show the wreck. As well, there was a chunk missing out of the top at the back. Having looked at this disaster it was time to start the restoration. Before you start, make sure you keep all the parts in a box so that none get lost. The first step is to thoroughly clean all the pieces of the cabinet. Clean, warm, soapy (kitchen detergent) water with cloudy ammonia in a ratio of about 9:1 is used with a scrubbing brush and an old toothbrush to get all the gunk off. Rinse each piece under cold water until it is clean. Small cracks need to be slightly prised apart and a pin or similar item slipped into each crack so that it can be cleaned to the best of your ability. The toothbrush is the best item for thoroughly cleaning out the cracks or any of the cracked surfac­es. Glue will not adhere through dirt and grime, so it is impera­tive to be very thorough. Now the job of gluing the cabinet together is undertaken. While the method to be described is not suitable in all cases, it will be a good starting point and restorers can adapt the method to individual cabinets. Photo 3 shows the cabinet and the bits necessary to hold it together as the glue hardens. You need a length of cord and a large rubber band cut out of an old car or bicycle inner tube. Get one from your favourite tyre store. The cord is tied to the rubber band as shown and the cord and band are wrapped around the cabinet to be glued. The cord is attached to the other side of the rubber band and its length adjusted so that reasonable ten­sion is applied via the rubber band to keep the cabinet firmly together. It is removed after the glue hardens. Have a trial run with the rubber band setup before apply­ing the glue to the broken edges of the cabinet. Having worked out how you will hold the cabinet together, dismantle the cord and rubber band and start the gluing process. Apply a bead of Araldite (TM) along the surfaces to be joined so that the glue is not proud on the outside surface of the cabinet, if at all possible. It dries a different colour to the cabinet and will show up as a visible line. Surplus Araldite can be wiped off with a cloth moistened with acetone. On the inside it doesn’t matter. This is not always an easy task as it is gooey and seems to go everywhere except where you want it and, of course, there is limited time to do the job. I’ve normally used 5-minute Araldite but with the rubber strap employed, the longer setting version could be used. If you have any doubts about the freshness of your Araldite, open a new batch. Leave the glue to harden over several hours with the holding strap on. Then take the strap off and check your progress so far. It is best to glue only one section at a time and leave just a small gap in the other surface to be joined as shown in the photograph. A couple Photo 2: the job looks even worse with broken pieces of the cabinet spread out. Photo 3: during gluing, the cabinet is held under tension by a cord and rubber band arrangement while the Araldite sets. Only do one join at a time. of matches will keep the second break apart. The Bakelite tends to distort when broken, so by doing the repair one surface at a time it is possible to align them more accurately and get a stronger join. Small cracks can be prised apart and a pin fitted to allow the glue to penetrate, as shown in photo 3 – in this case, above where the dial scale fits. Remove the pin as soon as the glue has filled the space. I have had some problems with the Araldite not having as much strength as expected. To get the maximum strength, mix the two components thoroughly, stirring them until the mixture goes milky. Continue mixing July 2001  91 together. It was only necessary to add a very small amount of black to the brown to get a reasonable match to the colour of the cabinet. With a small artist’s brush, paint the ice-cream sticks and let them dry. There was a small amount of excess glue in a corner near the grille which I couldn’t remove, so I also painted this to keep the cabinet a reasonably uniform colour. Once the paint is dry, use a small fine-toothed file to file down the irregular­ities in the paint finish. Paint and file around three times but don’t file or sand the last coat of paint. The finish will now look almost identical to the original Bakelite. Strengthening the cabinet Photo 4: ice-cream sticks were shaped and glued into the speaker grille gaps. Don’t laugh, the end result is effective. until the mixture again becomes clear, then apply it to the joins. The joins are now reasonably strong although not as strong as the areas where no breaks had occurred. The speaker grille in this cabinet was a real mess, looking a bit like a fighter who had most of his teeth knocked out. There were some pieces still with the cabinet and these were glued back into place with Araldite. The cabinet was stood on end so that the weight of the grille pieces would not cause them to move as the glue set; a messy job. Next, it was necessary to make some more grille pieces and in this case ice-cream sticks made almost ideal re­ placements. These were slightly shap­ed and cut to length, then glued into place – see photo 4. Using a small needle-nosed file it is possible to file away the excess glue once it has well and truly set. Painting the grille The ice-cream stick grille can now be painted. Before doing so, clean the area to be painted with methylated spirits. The ideal paint is oil-based, with a satin finish. This is not always possible to obtain in small tins. I had some black matt and some mission brown gloss enamel which I mixed Photo 5: the interior of the cabinet before fibreglass was applied to strengthen it. A strip of fibreglass matting is shown in the foreground. 92  Silicon Chip The next step is to strengthen the cabinet as the glue bond is not over the whole of the broken edges and hence is not as strong as the rest of the cabinet. Fibreglass matting and general purpose polyester resin are used to strengthen the joins. On the inside of the cabinet where the breaks were, chip away the excess Araldite with a knife or wood chisel. With 800 grade or similar wet and dry paper, sand along the glue joins for about a centimetre either side of the joins, then clean up with methylated spirits. The full list of materials and tools used for the strength­ ening of the cabinet are general purpose polyester resin, cata­ lyst hardener, fibreglass matting, pigment to suit the colour of the cabinet, acetone and a small stiff-bristled brush. The resin may be available in tins as small as 250ml and the hardener is usually available in bottles of around 30 to 50ml. Pigment comes in 50ml bottles or larger (you’ll use very little of it). Fibreglass matting is available in a variety of widths and density and a suitable type is shown in the photographs. Acetone is available in tins from around 250ml. Brushes and other materi­als are usually available from hardware stores. Alternatively, check with organisations that deal exclusively with fibreglass materials. The pigments are the hardest to obtain and may need to be ordered in. Dark brown is a good colour to start with but red and black may be necessary as well, as the exact colour may need to be made by mixing various colours. Photo 6: the missing section of the cabinet was replaced with resin applied to a strip of celluloid or acetate. The materials used in the repair are shown alongside it, less the fibreglass mat­ting. To match the colour of the Bakelite, put a small amount of the pigment on an inconspicuous part of the cabinet so that you can carefully compare the two. By adding red and/or black it should be possible to match most dark Bakelites. If you have trouble obtaining the materials locally, it could be worth­ while contacting Solid Solutions, 19 Ardena Court, Bentleigh, Vic 3204. Phone (03) 9579 2044. We are now at the stage of strengthening the cabinet. Cut a small strip of fibreglass matting around 20mm wide, as shown in photo 5, to match the length of the repaired crack. Pour one or two teaspoons of resin into a 35mm plastic film canister, then add around five drops of hardener and mix it well. Do not use too much catalyst/ hardener as it will cause the polyester resin to shrink. A 1% hardener by weight ratio equals one drop per five grams of resin. A 2% hardener by weight ratio equals two drops per five grams of resin and so on. The 1% mixture has a pot life of around 30 minutes and the 2% mixture around 15 minutes at 25°C. With a small stiff-bristled paintbrush, brush the mixture onto the sanded-down area along the glued joint, then place the matting along the joins. Put more resin onto the matting, working it into the matting by dabbing with the paintbrush so that it is thoroughly saturated with resin. The fibreglass can be pushed around to get it exactly where you want it. Then leave it to set. Clean the brush and the film canister container with ace­tone. The resin does not stick to the plastic. Further coats of resin can be put over the original coats and sanded so that an extremely smooth finish is obtained. The sanded area of the resin goes white but when another coat is applied, it reverts to the colour of the resin or if it has been pigmented, to the colour of the pigment. Plastic surgery That is the easy part. The next stage is the replacement of the missing bit of the cabinet. Obtain an acetate (celluloid) sheet from an art material supplier. The sheets are around 600mm square. Alternatively, you can use celluloid from a shirt box, or similar. Cut a piece just a bit bigger than the piece of cabinet that is missing. Attach it over the missing bit of the cabinet with masking tape – see photo 6. This photo also shows the materials needed to do the repairs. Fortunately this is a simple curve, so the sheet will follow it without problems. However, be quite careful in ensuring that the acetate sheet follows the curve precisely and is flush with the Bakelite that it is attached to. If it isn’t, the resin will seep between the acetate sheet and the Bakelite and give a step in the finish where the resin and the Bakelite butt up to one another. The resin will not adhere to the sheet. Where curves are complex, a Plaster of Paris mould would need to be made. I won’t go into how to do complex curves in this article – let’s just get a simple one right. Matching the pigment The next step is to match the pigment with the colour of the Bakelite, by mixing various colours until the right colour is obtained. For most dark Bakelites a mixture of dark brown, black and red will usually achieve a good match. Some fibreglass out­lets will mix pigments for a reasonable cost and this may be better than buying several tins or bottles of pigment. I didn’t have quite the correct colour pigment as can be seen in photo 7; my next cabinet repair will be better. This is then mixed into the next batch of resin and hardener used. This is paintJuly 2001  93 Photo 7: the rough edges of the fibre-glassed repaired cabinet section need to be sanded until they are smooth. Photo 8: this is how the repaired cabinet looked before the final cut and polish. ed onto the underside of the acetate sheet. Once this has set, put another pigmented layer on. Now cut a piece of fibreglass mat to overfill the broken section. Brush on another coat of resin, then lay the mat over the gap and overlap by about a centimetre onto the Bakelite either side of the gap. While it is still workable, put more resin onto the mat, making sure it is saturated. Use the paintbrush to dab at the matting, forcing the resin through any holes, thereby eliminating any air bubbles. Dabbing also eliminates any brush “drag”. 94  Silicon Chip Allow to set, then place another fibreglass mat into the gap and do the same as for the first mat. Perhaps use a little less hardener so that the setting time is extended. If quite an area is to be built up, talcum powder can be used as a filler. Once the resin has set, sand it so that it is reasonably smooth. Cut off any strands of fibreglass mat that protrude from the resin and clean the sanded material off. Coloured pigment can be added to the next coat but is not essential on the inside of the cabinet as the colour of the Bakelite still shows through. The last coat of resin will have pigment added to it to make sure the matting under it is completely disguised. Several layers of resin and fibreglass are applied until the material is around the same thickness as the Bakelite. The edge of the resin and fibreglass along the rear edge of the cabinet was then sanded until it was straight and smooth. Photo 7 shows the cabinet with the acetate removed and ready to be sanded. Another light coat of resin is applied to the back edge so that it is virtually the same colour as the rest of the cabinet. Repairing the cabinet exterior It is likely that there will be a few bubbles in the glue on the outside surface of the cabinet. To get rid of these bub­bles, use a reasonably fine file and working carefully, file the glue away. Be careful not to file the areas of the cabinet near the glued joint. The glue will file quite nicely and it is possi­ble to get it nearly flush with the cabinet. If the join is perfect there will be no gaps, so the surface will be smooth and continuous with no bumps. Finish off with fine wet and dry paper (grade 800 - 1200 - 2000). In many cases there will be some small gaps as the Bakel­ite may have splint­ ered on breaking and have very small pieces missing at the break. It may be necessary to fill these tiny gaps with some coloured resin. If for some reason the two sections of Bakelite on either side of the join are not level (this happens with some breaks), it is quite practical to use the file (with care) and the wet and dry paper to sand away some of the high side of the join to make it smooth. This is ultimately finished off with automobile cream cut and polish which will make the join hard to see – but not completely invisible. The cabinet looks a million dollars compared to what it looked before restoration. The next step is to use very fine (grade 800 - 1200 - 2000) wet and dry paper (wet in water) to remove any light scratches. When rubbing, don’t go too deep as it will put a dimple in the cabinet. If you can’t get a scratch out, try using a spirit-filled colour pen such as a “Texta Colour” to tint the scratch. Automotive cut and polish can also be used to remove the scratches but if you do use it you may need to use ELECTRONIC VALVE & TUBE COMPANY The Electronic Valve & Tube Company (EVATCO) stocks a large range of valves for vintage radio, amateur radio, industrial and small transmitting use. Major current brands such as SOV-TEK and SVETLANA are always stocked and we can supply some rare NOS (New - Old stock) brands such as Mullard, Telefunken, RCA and Philips. Hard to get high-voltage electrolytic capacitors and valve sockets are also available together with a wide range of books covering valve specifications, design and/or modification of valve audio amplifiers. Photo 9: this is the completed cabinet and receiver after its final polish. It’s not perfect but would you have thought that the mess in photo 1 could be restored to this standard? methylated spirits to get rid of the polish around where the spirit filled pen is to be used. The final polish won’t be done until the cabinet is all in one piece. The final polish It’s been a reasonably long process repairing the cabinet but it is really starting to look great when compared to the sorry heap of bits that we started with. I have found that car cut and polish is very good for giving a cabinet that last little bit of a lift. Firstly, make sure that there are no obvious scratches. If there are, use the fine wet and dry paper to get these out if you can. Once they are gone and the cabinet is smooth but dull, it is then time to do the cut and polish trick. Put some cut and polish compound onto a cotton rag and work on a small area of the cabinet, such as the top. Once it is nearly dry, use another cloth and polish the area with a circular motion – or rub the cloth backwards and forwards if there is a groove where you are working. Generally, do the cutting and polishing over the whole cabinet in sections, using the two loths. It can then be seen how the cabinet has come up from the above photo. It may be necessary to do further work on some sections to get all of the oxidised Bakelite off. The original rich Bakelite colour underneath the gunk will now be revealed – and doesn’t it look good! Fingers will mark the finish, so carefully polish the cabi­ net with a clean rag. Keep your fingers inside the cabinet if possible, to make sure the finish is not marred. Well, that’s about it. The cabinet, while not without some blemishes, is looking good as is shown in photos 8 & 9. The re­ceiver has considerable nostalgic value to the owner and he was thrilled with the end result. What more could I ask! Summary The method that I have described in this article is not the only way in which a Bakelite cabinet can be restored. It is a method that can achieve quite satisfying results and save many a set from an unworthy end. This was the first Bakelite repair job I have done with assistance and encouragement from Ralph Robertson. This shows that with care, you can confidently repair most damaged SC Bakelite cabinets. PO Box 487 Drysdale, Victoria 3222. Tel: (03) 5257 2297; Fax: (03) 5257 1773 Mob: 0417 143 167; email: evatco<at>mira.net New premises at: 76 Bluff Road, St Leonards, Vic 3223 P.C.B. Makers ! If you need: •  P.C.B. High Speed Drill •  3M Scotchmark Laser Labels •  P.C.B. Material – Negative or Positive acting •  Light Box – Single or Double Sided – Large or Small •  Etch Tank – Bubble •  Electronic Components and Equipment for TAFEs, Colleges and Schools •  Prompt and Economical Delivery •  FREE ADVICE ON ANY OF OUR PRODUCTS FROM DEDICATED PEOPLE WITH HANDS-ON EXPERIENCE We now stock Hawera Carbide Tool Bits KALEX 40 Wallis Ave E. Ivanhoe 3079 Ph (03) 9497 3422  FAX (03) 9499 2381 ALL MAJOR CREDIT CARDS ACCEPTED July 2001  95 Silicon Chip Back Issues April 1989: Auxiliary Brake Light Flasher; What You Need to Know About Capacitors; 32-Band Graphic Equaliser, Pt.2. May 1989: Build A Synthesised Tom-Tom; Biofeedback Monitor For Your PC; Simple Stub Filter For Suppressing TV Interference. July 1989: Exhaust Gas Monitor; Experimental Mains Hum Sniffers; Compact Ultrasonic Car Alarm; The NSW 86 Class Electrics. September 1989: 2-Chip Portable AM Stereo Radio (Uses MC13024 and TX7376P) Pt.1; High Or Low Fluid Level Detector; Studio Series 20-Band Stereo Equaliser, Pt.2. September 1993: Automatic Nicad Battery Charger/Discharger; Stereo Preamplifier With IR Remote Control, Pt.1; In-Circuit Transistor Tester; +5V to ±15V DC Converter; Remote-Controlled Cockroach. October 1993: Courtesy Light Switch-Off Timer For Cars; Wireless Microphone For Musicians; Stereo Preamplifier With IR Remote Control, Pt.2; Electronic Engine Management, Pt.1. May 1991: 13.5V 25A Power Supply For Transceivers; Stereo Audio Expander; Fluorescent Light Simulator For Model Railways; How To Install Multiple TV Outlets, Pt.1. July 1991: Loudspeaker Protector For Stereo Amplifiers; 4-Channel Lighting Desk, Pt.2; How To Install Multiple TV Outlets, Pt.2; Tuning In To Satellite TV, Pt.2. September 1991: Digital Altimeter For Gliders & Ultralights; Ultrasonic Switch For Mains Appliances; The Basics Of A/D & D/A Conversion; Plotting The Course Of Thunderstorms. October 1989: FM Radio Intercom For Motorbikes Pt.1; GaAsFet Preamplifier For Amateur TV; 2-Chip Portable AM Stereo Radio, Pt.2. October 1991: Build A Talking Voltmeter For Your PC, Pt.1; SteamSound Simulator For Model Railways Mk.II; Magnetic Field Strength Meter; Digital Altimeter For Gliders, Pt.2; Military Applications Of R/C Aircraft. November 1989: Radfax Decoder For Your PC (Displays Fax, RTTY & Morse); FM Radio Intercom For Motorbikes, Pt.2; 2-Chip Portable AM Stereo Radio, Pt.3; Floppy Disk Drive Formats & Options. November 1991: Colour TV Pattern Generator, Pt.1; A Junkbox 2-Valve Receiver; Flashing Alarm Light For Cars; Digital Altimeter For Gliders, Pt.3; Build A Talking Voltmeter For Your PC, Pt.2. January 1990: High Quality Sine/Square Oscillator; Service Tips For Your VCR; Phone Patch For Radio Amateurs; Active Antenna Kit; Designing UHF Transmitter Stages. December 1991: TV Transmitter For VCRs With UHF Modulators; Infrared Light Beam Relay; Colour TV Pattern Generator, Pt.2; Index To Volume 4. February 1990: A 16-Channel Mixing Desk; Build A High Quality Audio Oscillator, Pt.2; The Incredible Hot Canaries; Random Wire Antenna Tuner For 6 Metres; Phone Patch For Radio Amateurs, Pt.2. January 1992: 4-Channel Guitar Mixer; Adjustable 0-45V 8A Power Supply, Pt.1; Baby Room Monitor/FM Transmitter; Experiments For Your Games Card. March 1990: Delay Unit For Automatic Antennas; Workout Timer For Aerobics Classes; 16-Channel Mixing Desk, Pt.2; Using The UC3906 SLA Battery Charger IC. March 1992: TV Transmitter For VHF VCRs; Thermostatic Switch For Car Radiator Fans; Coping With Damaged Computer Directories; Valve Substitution In Vintage Radios. April 1990: Dual Tracking ±50V Power Supply; Voice-Operated Switch (VOX) With Delayed Audio; 16-Channel Mixing Desk, Pt.3; Active CW Filter; Servicing Your Microwave Oven. April 1992: IR Remote Control For Model Railroads; Differential Input Buffer For CROs; Understanding Computer Memory; Aligning Vintage Radio Receivers, Pt.1. June 1990: Multi-Sector Home Burglar Alarm; Build A Low-Noise Universal Stereo Preamplifier; Load Protector For Power Supplies. June 1992: Multi-Station Headset Intercom, Pt.1; Video Switcher For Camcorders & VCRs; IR Remote Control For Model Railroads, Pt.3; 15-Watt 12-240V Inverter; A Look At Hard Disk Drives. July 1990: Digital Sine/Square Generator, Pt.1 (covers 0-500kHz); Burglar Alarm Keypad & Combination Lock; Build A Simple Electronic Die; A Low-Cost Dual Power Supply. August 1990: High Stability UHF Remote Transmitter; Universal Safety Timer For Mains Appliances (9 Minutes); Horace The Electronic Cricket; Digital Sine/Square Generator, Pt.2. September 1990: A Low-Cost 3-Digit Counter Module; Build A Simple Shortwave Converter For The 2-Metre Band; The Care & Feeding Of Nicad Battery Packs (Getting The Most From Nicad Batteries). October 1990: The Dangers of PCBs; Low-Cost Siren For Burglar Alarms; Dimming Controls For The Discolight; Surfsound Simulator; DC Offset For DMMs; NE602 Converter Circuits. November 1990: Connecting Two TV Sets To One VCR; Build An Egg Timer; Low-Cost Model Train Controller; 1.5V To 9V DC Converter; Introduction To Digital Electronics; A 6-Metre Amateur Transmitter. December 1990: 100W DC-DC Converter For Car Amplifiers; Wiper Pulser For Rear Windows; 4-Digit Combination Lock; 5W Power Amplifier For The 6-Metre Amateur Transmitter; Index To Volume 3. \January 1991: Fast Charger For Nicad Batteries, Pt.1; Have Fun With The Fruit Machine (Simple Poker Machine); Build A Two-Tone Alarm Module; The Dangers of Servicing Microwave Ovens. November 1993: High Efficiency Inverter For Fluorescent Tubes; Stereo Preamplifier With IR Remote Control, Pt.3; Siren Sound Generator; Engine Management, Pt.2; Experiments For Games Cards. December 1993: Remote Controller For Garage Doors; Build A LED Stroboscope; Build A 25W Audio Amplifier Module; A 1-Chip Melody Generator; Engine Management, Pt.3; Index To Volume 6. January 1994: 3A 40V Variable Power Supply; Solar Panel Switching Regulator; Printer Status Indicator; Mini Drill Speed Controller; Stepper Motor Controller; Active Filter Design; Engine Management, Pt.4. February 1994: Build A 90-Second Message Recorder; 12-240VAC 200W Inverter; 0.5W Audio Amplifier; 3A 40V Adjustable Power Supply; Engine Management, Pt.5; Airbags In Cars – How They Work. March 1994: Intelligent IR Remote Controller; 50W (LM3876) Audio Amplifier Module; Level Crossing Detector For Model Railways; Voice Activated Switch For FM Microphones; Engine Management, Pt.6. April 1994: Sound & Lights For Model Railway Level Crossings; Discrete Dual Supply Voltage Regulator; Universal Stereo Preamplifier; Digital Water Tank Gauge; Engine Management, Pt.7. May 1994: Fast Charger For Nicad Batteries; Induction Balance Metal Locator; Multi-Channel Infrared Remote Control; Dual Electronic Dice; Simple Servo Driver Circuits; Engine Management, Pt.8. June 1994: 200W/350W Mosfet Amplifier Module; A Coolant Level Alarm For Your Car; 80-Metre AM/CW Transmitter For Amateurs; Converting Phono Inputs To Line Inputs; PC-Based Nicad Battery Monitor; Engine Management, Pt.9. July 1994: Build A 4-Bay Bow-Tie UHF TV Antenna; PreChamp 2-Transistor Preamplifier; Steam Train Whistle & Diesel Horn Simulator; 6V SLA Battery Charger; Electronic Engine Management, Pt.10. August 1994: High-Power Dimmer For Incandescent Lights; Microprocessor-Controlled Morse Keyer; Dual Diversity Tuner For FM Microphones, Pt.1; Nicad Zapper (For Resurrecting Nicad Batteries); Electronic Engine Management, Pt.11. August 1992: Automatic SLA Battery Charger; Miniature 1.5V To 9V DC Converter; 1kW Dummy Load Box For Audio Amplifiers; Troubleshooting Vintage Radio Receivers; The MIDI Interface Explained. September 1994: Automatic Discharger For Nicad Battery Packs; MiniVox Voice Operated Relay; Image Intensified Night Viewer; AM Radio For Weather Beacons; Dual Diversity Tuner For FM Microphones, Pt.2; Electronic Engine Management, Pt.12. October 1992: 2kW 24VDC - 240VAC Sinewave Inverter; Multi-Sector Home Burglar Alarm, Pt.2; Mini Amplifier For Personal Stereos; A Regulated Lead-Acid Battery Charger. October 1994: How Dolby Surround Sound Works; Dual Rail Variable Power Supply; Build A Talking Headlight Reminder; Electronic Ballast For Fluorescent Lights; Electronic Engine Management, Pt.13. January 1993: Flea-Power AM Radio Transmitter; High Intensity LED Flasher For Bicycles; 2kW 24VDC To 240VAC Sinewave Inverter, Pt.4; Speed Controller For Electric Models, Pt.3. November 1994: Dry Cell Battery Rejuvenator; Novel Alphanumeric Clock; 80-Metre DSB Amateur Transmitter; Twin-Cell Nicad Discharger (See May 1993); How To Plot Patterns Direct to PC Boards. February 1993: Three Projects For Model Railroads; Low Fuel Indicator For Cars; Audio Level/VU Meter (LED Readout); An Electronic Cockroach; 2kW 24VDC To 240VAC Sinewave Inverter, Pt.5. December 1994: Easy-To-Build Car Burglar Alarm; Three-Spot Low Distortion Sinewave Oscillator; Clifford – A Pesky Electronic Cricket; Remote Control System for Models, Pt.1; Index to Vol.7. March 1993: Solar Charger For 12V Batteries; Alarm-Triggered Security Camera; Reaction Trainer; Audio Mixer for Camcorders; A 24-Hour Sidereal Clock For Astronomers. January 1995: Sun Tracker For Solar Panels; Battery Saver For Torches; Dolby Pro-Logic Surround Sound Decoder, Pt.2; Dual Channel UHF Remote Control; Stereo Microphone Pre­amp­lifier. April 1993: Solar-Powered Electric Fence; Audio Power Meter; Three-Function Home Weather Station; 12VDC To 70VDC Converter; Digital Clock With Battery Back-Up. February 1995: 50-Watt/Channel Stereo Amplifier Module; Digital Effects Unit For Musicians; 6-Channel Thermometer With LCD Readout; Wide Range Electrostatic Loudspeakers, Pt.1; Oil Change Timer For Cars; Remote Control System For Models, Pt.2. June 1993: AM Radio Trainer, Pt.1; Remote Control For The Woofer Stopper; Digital Voltmeter For Cars; Windows-Based Logic Analyser. March 1991: Transistor Beta Tester Mk.2; A Synthesised AM Stereo Tuner, Pt.2; Multi-Purpose I/O Board For PC-Compatibles; Universal Wideband RF Preamplifier For Amateur Radio & TV. July 1993: Single Chip Message Recorder; Light Beam Relay Extender; AM Radio Trainer, Pt.2; Quiz Game Adjudicator; Windows-Based Logic Analyser, Pt.2; Antenna Tuners – Why They Are Useful. April 1991: Steam Sound Simulator For Model Railroads; Simple 12/24V Light Chaser; Synthesised AM Stereo Tuner, Pt.3; A Practical Approach To Amplifier Design, Pt.2. August 1993: Low-Cost Colour Video Fader; 60-LED Brake Light Array; Microprocessor-Based Sidereal Clock; A Look At Satellites & Their Orbits. March 1995: 50 Watt Per Channel Stereo Amplifier, Pt.1; Subcarrier Decoder For FM Receivers; Wide Range Electrostatic Loudspeakers, Pt.2; IR Illuminator For CCD Cameras; Remote Control System For Models, Pt.3; Simple CW Filter. April 1995: FM Radio Trainer, Pt.1; Photographic Timer For Dark­ rooms; Balanced Microphone Preamp. & Line Filter; 50W/Channel Stereo Amplifier, Pt.2; Wide Range Electrostatic Loudspeakers, Pt.3; 8-Channel Decoder For Radio Remote Control. ORDER FORM Please send thethe following back issues: Please send following back issues:      ____________________________________________________________ Enclosed is my cheque/money order for $­______or please debit my:  ❏ Bankcard  ❏ Visa Card  ❏ Master Card Card No. Signature ___________________________ Card expiry date_____ /______ Name ______________________________ Phone No (___) ____________ PLEASE PRINT Street ______________________________________________________ Suburb/town _______________________________ Postcode ___________ 96  Silicon Chip 10% OF F SUBSCR TO IB OR IF Y ERS OU 10 OR M BUY ORE Note: prices include postage & packing Australia ....................... $A7.70 (incl. GST) Overseas (airmail) ............................ $A10 Detach and mail to: Silicon Chip Publications, PO Box 139, Collaroy, NSW, Australia 2097. Or call (02) 9979 5644 & quote your credit card details or fax the details to (02) 9979 6503. Email: silchip<at>siliconchip.com.au May 1995: Build A Guitar Headphone Amplifier; FM Radio Trainer, Pt.2; Transistor/Mosfet Tester For DMMs; A 16-Channel Decoder For Radio Remote Control; Introduction to Satellite TV. October 1997: Build A 5-Digit Tachometer; Add Central Locking To Your Car; PC-Controlled 6-Channel Voltmeter; 500W Audio Power Amplifier, Pt.3; Customising The Windows 95 Start Menu. June 1995: Build A Satellite TV Receiver; Train Detector For Model Railways; 1W Audio Amplifier Trainer; Low-Cost Video Security System; Multi-Channel Radio Control Transmitter For Models, Pt.1. November 1997: Heavy Duty 10A 240VAC Motor Speed Controller; Easy-To-Use Cable & Wiring Tester; Build A Musical Doorbell; Replacing Foam Speaker Surrounds; Understanding Electric Lighting Pt.1. July 1995: Electric Fence Controller; How To Run Two Trains On A Single Track (Incl. Lights & Sound); Setting Up A Satellite TV Ground Station; Build A Reliable Door Minder. December 1997: Build A Speed Alarm For Your Car; Two-Axis Robot With Gripper; Loudness Control For Car Hifi Systems; Stepper Motor Driver With Onboard Buffer; Power Supply For Stepper Motor Cards; Understanding Electric Lighting Pt.2; Index To Volume 10. August 1995: Fuel Injector Monitor For Cars; Gain Controlled Microphone Preamp; Audio Lab PC-Controlled Test Instrument, Pt.1; How To Identify IDE Hard Disk Drive Parameters. September 1995: Railpower Mk.2 Walkaround Throttle For Model Railways, Pt.1; Keypad Combination Lock; The Vader Voice; Jacob’s Ladder Display; Audio Lab PC-Controlled Test Instrument, Pt.2. October 1995: 3-Way Bass Reflex Loudspeaker System; Railpower Mk.2 Walkaround Throttle For Model Railways, Pt.2; Fast Charger For Nicad Batteries; Digital Speedometer & Fuel Gauge For Cars, Pt.1. November 1995: Mixture Display For Fuel Injected Cars; CB Trans­verter For The 80M Amateur Band, Pt.1; PIR Movement Detector; Digital Speedometer & Fuel Gauge For Cars, Pt.2. December 1995: Engine Immobiliser; 5-Band Equaliser; CB Transverter For The 80M Amateur Band, Pt.2; Subwoofer Controller; Knock Sensing In Cars; Index To Volume 8. January 1998: Build Your Own 4-Channel Lightshow, Pt.1 (runs off 12VDC or 12VAC); Command Control System For Model Railways, Pt.1; Pan Controller For CCD Cameras; Build A One Or Two-Lamp Flasher; Understanding Electric Lighting, Pt.3. February 1998: Multi-Purpose Fast Battery Charger, Pt.1; Telephone Exchange Simulator For Testing; Command Control System For Model Railways, Pt.2; Build Your Own 4-Channel Lightshow, Pt.2; Understanding Electric Lighting, Pt.4. April 1998: Automatic Garage Door Opener, Pt.1; 40V 8A Adjustable Power Supply, Pt.1; PC-Controlled 0-30kHz Sinewave Generator; Build A Laser Light Show; Understanding Electric Lighting; Pt.6. May 1998: Troubleshooting Your PC, Pt.1; Build A 3-LED Logic Probe; Automatic Garage Door Opener, Pt.2; Command Control For Model Railways, Pt.4; 40V 8A Adjustable Power Supply, Pt.2. January 1996: Surround Sound Mixer & Decoder, Pt.1; Magnetic Card Reader; Build An Automatic Sprinkler Controller; IR Remote Control For The Railpower Mk.2; Recharging Nicad Batteries For Long Life. June 1998: Troubleshooting Your PC, Pt.2; Understanding Electric Lighting, Pt.7; Universal High Energy Ignition System; The Roadies’ Friend Cable Tester; Universal Stepper Motor Controller; Command Control For Model Railways, Pt.5. April 1996: Cheap Battery Refills For Mobile Telephones; 125W Audio Power Amplifier Module; Knock Indicator For Leaded Petrol Engines; Multi-Channel Radio Control Transmitter; Pt.3; Cathode Ray Oscilloscopes, Pt.2. July 1998: Troubleshooting Your PC, Pt.3 (Installing A Modem And Solving Problems); Build A Heat Controller; 15-Watt Class-A Audio Amplifier Module; Simple Charger For 6V & 12V SLA Batteries; Automatic Semiconductor Analyser; Understanding Electric Lighting, Pt.8. May 1996: Upgrading The CPU In Your PC; High Voltage Insulation Tester; Knightrider Bi-Directional LED Chaser; Simple Duplex Intercom Using Fibre Optic Cable; Cathode Ray Oscilloscopes, Pt.3. August 1998: Troubleshooting Your PC, Pt.4 (Adding Extra Memory); Build The Opus One Loudspeaker System; Simple I/O Card With Automatic Data Logging; Build A Beat Triggered Strobe; A 15-Watt Per Channel Class-A Stereo Amplifier. June 1996: BassBox CAD Loudspeaker Software Reviewed; Stereo Simulator (uses delay chip); Rope Light Chaser; Low Ohms Tester For Your DMM; Automatic 10A Battery Charger. July 1996: Build A VGA Digital Oscilloscope, Pt.1; Remote Control Extender For VCRs; 2A SLA Battery Charger; 3-Band Parametric Equaliser; Single Channel 8-bit Data Logger. August 1996: Introduction to IGBTs; Electronic Starter For Fluores­cent Lamps; VGA Oscilloscope, Pt.2; 350W Amplifier Module; Masthead Amplifier For TV & FM; Cathode Ray Oscilloscopes, Pt.4. September 1998: Troubleshooting Your PC, Pt.5 (Software Problems & DOS Games); A Blocked Air-Filter Alarm; A Waa-Waa Pedal For Your Guitar; Build A Plasma Display Or Jacob’s Ladder; Gear Change Indicator For Cars; Capacity Indicator For Rechargeable Batteries. October 1998: Lab Quality AC Millivoltmeter, Pt.1; PC-Controlled StressO-Meter; Versatile Electronic Guitar Limiter; 12V Trickle Charger For Float Conditions; Adding An External Battery Pack To Your Flashgun. September 1996: VGA Oscilloscope, Pt.3; IR Stereo Headphone Link, Pt.1; High Quality PA Loudspeaker; 3-Band HF Amateur Radio Receiver; Cathode Ray Oscilloscopes, Pt.5. November 1998: The Christmas Star (Microprocessor-Controlled Christmas Decoration); A Turbo Timer For Cars; Build A Poker Machine, Pt.1; FM Transmitter For Musicians; Lab Quality AC Millivoltmeter, Pt.2; Setting Up A LAN Using TCP/IP; Understanding Electric Lighting, Pt.9; Improving AM Radio Reception, Pt.1. October 1996: Send Video Signals Over Twisted Pair Cable; Power Control With A Light Dimmer; 600W DC-DC Converter For Car Hifi Systems, Pt.1; IR Stereo Headphone Link, Pt.2; Build A Multi-Media Sound System, Pt.1; Multi-Channel Radio Control Transmitter, Pt.8. December 1998: Protect Your Car With The Engine Immobiliser Mk.2; Thermocouple Adaptor For DMMs; A Regulated 12V DC Plugpack; Build Your Own Poker Machine, Pt.2; Improving AM Radio Reception, Pt.2; Mixer Module For F3B Glider Operations. November 1996: Adding A Parallel Port To Your Computer; 8-Channel Stereo Mixer, Pt.1; Low-Cost Fluorescent Light Inverter; How To Repair Domestic Light Dimmers; Build A Multi-Media Sound System, Pt.2; 600W DC-DC Converter For Car Hifi Systems, Pt.2. January 1999: High-Voltage Megohm Tester; Getting Started With BASIC Stamp; LED Bargraph Ammeter For Cars; Keypad Engine Immobiliser; Improving AM Radio Reception, Pt.3; Electric Lighting, Pt.10 December 1996: Active Filter Cleans Up Your CW Reception; A Fast Clock For Railway Modellers; Laser Pistol & Electronic Target; Build A Sound Level Meter; 8-Channel Stereo Mixer, Pt.2; Index To Volume 9. February 1999: Installing A Computer Network; Making Front Panels For Your Projects; Low Distortion Audio Signal Generator, Pt.1; Command Control Decoder For Model Railways; Build A Digital Capacitance Meter; Build A Remote Control Tester; Electric Lighting, Pt.11. January 1997: How To Network Your PC; Control Panel For Multiple Smoke Alarms, Pt.1; Build A Pink Noise Source; Computer Controlled Dual Power Supply, Pt.1; Digi-Temp Monitors Eight Temperatures. February 1997: Cathode Ray Oscilloscopes, Pt.6; PC-Con­trolled Moving Message Display; Computer Controlled Dual Power Supply, Pt.2; The Alert-A-Phone Loud Sounding Telephone Alarm; Build A Control Panel For Multiple Smoke Alarms, Pt.2. March 1997: Driving A Computer By Remote Control; Plastic Power PA Amplifier (175W); Signalling & Lighting For Model Railways; Build A Jumbo LED Clock; Cathode Ray Oscilloscopes, Pt.7. April 1997: Simple Timer With No ICs; Digital Voltmeter For Cars; Loudspeaker Protector For Stereo Amplifiers; Model Train Controller; A Look At Signal Tracing; Pt.1; Cathode Ray Oscilloscopes, Pt.8. May 1997: Neon Tube Modulator For Light Systems; Traffic Lights For A Model Intersection; The Spacewriter – It Writes Messages In Thin Air; A Look At Signal Tracing; Pt.2; Cathode Ray Oscilloscopes, Pt.9. June 1997: PC-Controlled Thermometer/Thermostat; Colour TV Pattern Generator, Pt.1; Build An Audio/RF Signal Tracer; High-Current Speed Controller For 12V/24V Motors; Manual Control Circuit For A Stepper Motor; Cathode Ray Oscilloscopes, Pt.10. July 1997: Infrared Remote Volume Control; A Flexible Interface Card For PCs; Points Controller For Model Railways; Colour TV Pattern Generator, Pt.2; An In-Line Mixer For Radio Control Receivers. August 1997: The Bass Barrel Subwoofer; 500 Watt Audio Power Amplifier Module; A TENs Unit For Pain Relief; Addressable PC Card For Stepper Motor Control; Remote Controlled Gates For Your Home. September 1997: Multi-Spark Capacitor Discharge Ignition; 500W Audio Power Amplifier, Pt.2; A Video Security System For Your Home; PC Card For Controlling Two Stepper Motors; HiFi On A Budget. March 1999: Getting Started With Linux; Pt.1; Build A Digital Anemometer; 3-Channel Current Monitor With Data Logging; Simple DIY PIC Programmer; Easy-To-Build Audio Compressor; Low Distortion Audio Signal Generator, Pt.2; Electric Lighting, Pt.12. April 1999: Getting Started With Linux; Pt.2; High-Power Electric Fence Controller; Bass Cube Subwoofer; Programmable Thermostat/ Thermometer; Build An Infrared Sentry; Rev Limiter For Cars; Electric Lighting, Pt.13; Autopilots For Radio-Controlled Model Aircraft. May 1999: The Line Dancer Robot; An X-Y Table With Stepper Motor Control, Pt.1; Three Electric Fence Testers; Heart Of LEDs; Build A Carbon Monoxide Alarm; Getting Started With Linux; Pt.3. June 1999: FM Radio Tuner Card For PCs; X-Y Table With Stepper Motor Control, Pt.2; Programmable Ignition Timing Module For Cars, Pt.1; Hard Disk Drive Upgrades Without Reinstalling Software; What Is A Groundplane Antenna?; Getting Started With Linux; Pt.4. July 1999: Build A Dog Silencer; 10µH to 19.99mH Inductance Meter; Build An Audio-Video Transmitter; Programmable Ignition Timing Module For Cars, Pt.2; XYZ Table With Stepper Motor Control, Pt.3. August 1999: Remote Modem Controller; Daytime Running Lights For Cars; Build A PC Monitor Checker; Switching Temperature Controller; XYZ Table With Stepper Motor Control, Pt.4; Electric Lighting, Pt.14. September 1999: Automatic Addressing On TCP/IP Networks; Autonomouse The Robot, Pt.1; Voice Direct Speech Recognition Module; Digital Electrolytic Capacitance Meter; XYZ Table With Stepper Motor Control, Pt.5; Peltier-Powered Can Cooler. October 1999: Sharing A Modem For Internet & Email Access (WinGate); Build The Railpower Model Train Controller, Pt.1; Semiconductor Curve Tracer; Autonomouse The Robot, Pt.2; XYZ Table With Stepper Motor Control, Pt.6; Introducing Home Theatre. November 1999: Electric Lighting, Pt.15; Setting Up An Email Server; Speed Alarm For Cars, Pt.1; Multi-Colour LED Christmas Tree; Build An Intercom Station Expander; Foldback Loudspeaker System For Musicians; Railpower Model Train Controller, Pt.2. December 1999: Internet Connection Sharing Using Hardware; Electric Lighting, Pt.16; Build A Solar Panel Regulator; The PC Powerhouse (gives fixed +12V, +9V, +6V & +5V rails); The Fortune Finder Metal Locator; Speed Alarm For Cars, Pt.2; Railpower Model Train Controller, Pt.3; Index To Volume 12. January 2000: Spring Reverberation Module; An Audio-Video Test Generator; Build The Picman Programmable Robot; A Parallel Port Interface Card; Off-Hook Indicator For Telephone Lines. February 2000: Multi-Sector Sprinkler Controller; A Digital Voltmeter For Your Car; An Ultrasonic Parking Radar; Build A Safety Switch Checker; Build A Sine/Square Wave Oscillator; Marantz SR-18 Home Theatre Receiver (Review); The “Hot Chip” Starter Kit (Review). March 2000: Doing A Lazarus On An Old Computer; Ultra Low Distortion 100W Amplifier Module, Pt.1; Electronic Wind Vane With 16-LED Display; Glowplug Driver For Powered Models; The OzTrip Car Computer, Pt.1; Multisim Circuit Design & Simulation Package (Review). April 2000: A Digital Tachometer For Your Car; RoomGuard – A LowCost Intruder Alarm; Build A Hot wire Cutter; The OzTrip Car Computer, Pt.2; Build A Temperature Logger; Atmel’s ICE 200 In-Circuit Emulator; How To Run A 3-Phase Induction Motor From 240VAC. May 2000: Ultra-LD Stereo Amplifier, Pt.2; Build A LED Dice (With PIC Microcontroller); Low-Cost AT Keyboard Translator (Converts IBM Scan-Codes To ASCII); 50A Motor Speed Controller For Models; What’s Inside A Furby. June 2000: Automatic Rain Gauge With Digital Readout; Parallel Port VHF FM Receiver; Li’l Powerhouse Switchmode Power Supply (1.23V to 40V) Pt.1; CD Compressor For Cars Or The Home. July 2000: A Moving Message Display; Compact Fluorescent Lamp Driver; El-Cheapo Musicians’ Lead Tester; Li’l Powerhouse Switchmode Power Supply (1.23V to 40V) Pt.2; Say Bye-Bye To Your 12V Car Battery. August 2000: Build A Theremin For Really Eeerie Sounds; Come In Spinner (writes messages in “thin-air”); Loudspeaker Protector & Fan Controller For The Ultra-LD Stereo Amplifier; Proximity Switch For 240VAC Lamps; Structured Cabling For Computer Networks. September 2000: Build A Swimming Pool Alarm; An 8-Channel PC Relay Board; Fuel Mixture Display For Cars, Pt.1; Protoboards – The Easy Way Into Electronics, Pt.1; Cybug The Solar Fly; Network Troubleshooting With Fluke’s NetTool. October 2000: Guitar Jammer For Practice & Jam Sessions; Booze Buster Breath Tester; A Wand-Mounted Inspection Camera); Installing A Free-Air Subwoofer In Your Car; Fuel Mixture Display For Cars, Pt.2; Protoboards – The Easy Way Into Electronics, Pt.2. November 2000: Santa & Rudolf Chrissie Display; 2-Channel Guitar Preamplifier, Pt.1; Message Bank & Missed Call Alert; Electronic Thermostat; Protoboards – The Easy Way Into Electronics, Pt.3. December 2000: Home Networking For Shared Internet Access; Build A Bright-White LED Torch; 2-Channel Guitar Preamplifier, Pt.2 (Digital Reverb); Driving An LCD From The Parallel Port; Build A morse Clock; Protoboards – The Easy Way Into Electronics, Pt.4; Index To Vol.13. January 2001: LP Resurrection – Transferring LPs & Tapes To CD; The LP Doctor – Clean Up Clicks & Pops, Pt.1; Arbitrary Waveform Generator; 2-Channel Guitar Preamplifier, Pt.3; PIC Programmer & TestBed; Wireless Networking. February 2001: How To Observe Meteors Using Junked Gear; An Easy Way To Make PC Boards; L’il Pulser Train Controller; Midi-Mate – A MIDI Interface For PCs; Build The Bass Blazer; 2-Metre Elevated Groundplane Antenna; The LP Doctor – Clean Up Clicks & Pops, Pt.2. March 2001: Driving Your Phone From A PC; Making Photo Resist PC Boards At Home; Big-Digit 12/24 Hour Clock; Parallel Port PIC Programmer & Checkerboard; Protoboards – The Easy Way Into Electronics, Pt.5; More MIDI – A Simple MIDI Expansion Box. April 2001: A GPS Module For Your PC; Dr Video – An Easy-To-Build Video Stabiliser; A Tremolo Unit For Musicians; Minimitter FM Stereo Transmitter; Intelligent Nicad Battery Charger; Computer Tips – Tweaking Internet Connection Sharing. May 2001: Powerful 12V Mini Stereo Amplifier; Microcontroller-Based 4-Digit Counter Modules; Two White-LED Torches To Build; A Servo With Lots Of Grunt; PowerPak – A Multi-Voltage Power Supply; Using Linux To Share An Internet Connection, Pt.1; Computer Tips – Tweaking Windows With TweakUI. June 2001: Fast Universal Battery Charger, Pt.1; Phonome – Call, Listen In & Switch Devices On & Off; L’il Snooper – A low-Cost Austomatic Camera Switcher; Build a PC Games Port Tester; Using Linux To Share An Internet Connection, Pt.2; A PC To Die For – And You Can Build It Yourself; New Generation Pilotless Aircraft. PLEASE NOTE: November 1987 to March 1989, June 1989, August 1989, December 1989, May 1990, February 1991, June 1991, August 1991, February 1992, July 1992, September 1992, November 1992, December 1992, May 1993, February 1996 and March 1998 are now sold out. All other issues are presently in stock. For readers wanting articles from sold-out issues, we can supply photostat copies (or tear sheets) at $7.70 per article (includes p&p). When supplying photostat articles or back copies, we automatically supply any relevant notes & errata at no extra charge. A complete index to all articles published to date is available on floppy disk for $11 including p&p, or can be downloaded free from our web site: www.siliconchip.com.au July 2001  97 ASK SILICON CHIP Got a technical problem? Can’t understand a piece of jargon or some technical principle? Drop us a line and we’ll answer your question. Write to: Ask Silicon Chip, PO Box 139, Collaroy Beach, NSW 2097. Engine immobiliser for diesels can supply the back issues for $7.70 each, including postage. Are the various kits about based on your December 1998 Engine Immobiliser Mk2 (ie, Jaycar KC-5255) suitable for diesel engines? It appears to me that this circuit only works with coil-equipped cars. If it won’t be suitable, is there an alternative? (W. M., via email). •  As it stands, the immobiliser is set to kill the spark from the ignition coil. To make it work on a diesel you would have to make it kill the signal to the injectors or turn off the fuel pump to the fuel rail. Probably the easiest method would be to turn off the fuel pump using a suitably rated relay driven by the output transistor Q1. Fridge interference to audio system Low-powered surround sound system wanted Can you suggest a project for a reasonably low-powered 20-50W/channel amplifier for a surround sound system. (J. E., via email). •  Have a look at the 20W amp module in the December 1993 issue and/or the 40W/50W module in the March 1994 issue; also the twin 50W module in the February 1995 issue. All modules are presently available from Altronics. We White LED torch modifications I constructed the White LED Torch (described December 2000) from a Dick Smith Electronics kit. It works brilliantly. I have two questions on it. Is it possible to run the LED at 20mA+ from a 1.2V rechargeable cell with minor changes to the circuit? This would make the unit more useful on long trips away from services. Can it run, with modification, from a 3V source, allowing incorpo­ration into a combined radio/torch setup? (H. J., via email). •  The White LED Torch can be 98  Silicon Chip I have been having trouble with loud ‘pops’ in my stereo system when the fridge switches off. The system includes the “Electronics Australia” Pro Series One power amplifier and Pro Series Two preamplifier and a High Definition Audio device (ex Jaycar) installed between preamp output and power amp input. I have installed some varistors on the 240VAC input side of the power amplifier and poly switches on the output side of the amplifier. The fridge has an electromechanical timer installed to control the compressor & defrost cycle (I think). These ‘pops’ don’t always occur but are definitely coming from the fridge through the mains and into my stereo amplifier. Can I damp the contacts of the timer in the fridge with a series RC network to remove the spike that I assume occurs when they go open circuit? (C. L., via email). •  Connecting your audio gear via a mains filter might be a cure but we suspect that the amplifier or its preamp are picking up interference operated from 1.2V by shorting out resistor R1. This will increase the current drive to the LED. Essentially, the current is limited by the DC resistance of inductor L1 since this determines the saturation current. Winding your own using the Xenon tube transformer former will enable you to increase the LED current when using a 1.2V supply. You would need to use 250 turns of 0.25mm enamelled copper wire (rather than the 0.16mm wire specified) on the bare former. You could run the torch from 3V but resistor R1 should then be increased to 4.7Ω. radiated from the mains wiring each time the fridge clicks off. Whether or not a ‘pop’ occurs depends on when in each cycle of the 240VAC mains waveform the fridge actually switches off. There is probably little point in trying to suppress interference at the switch – we expect it already has these components. You will have to do some detective work to figure out how the interference is getting into your system. For example, is it getting in via the speaker leads? You can test this by discon­ necting the speakers and listening to your system via the head­phones. Is it getting in via the preamp? Disconnect the preamp and see if clicks are still picked up. Then you might find that you can cure the problem by winding the offending leads through ferrite toroids. In the worst case though, it may be necessary to modify the input and output stages of the amp and preamp to completely stop the problem. Some designers exacerbate these problems by designing their circuits with excessive bandwidth. Trouble with quiescent current setting I’ve been testing one of the output modules for the Ultra-LD 100W Amplifier (described in the March, May & August 2000 issues of SILICON CHIP) and I am having trouble with the quiescent current. When I measure the voltage across the 220Ω 5W resistor with VR1 fully anticlockwise, the lowest voltage I get is 0.68V. If I leave the DMM attached for a few minutes, the voltage rises to 9.3V then sort of cycles between that and 8.3V. Is this because I haven’t attached the heatsink yet? There are great differences in the temperatures of each pair of the MJL devices. Out of each pair, one is too hot to touch, the other is lukewarm or cold. The voltages across the 1.5Ω resistors stablilise at 13-14mV, not 7.5mV. Is this all because I don’t have the heatsink attached? (D. M., via email). must have the heatsinks attached before you can make any sense of the quiescent current adjustment. What happens is that Q10, the Vbe multiplier, monitors the temperature of the output transistors and adjusts the bias accordingly. Q10 can’t work properly if the heatsink is not fitted. •  You Hands-free phone amplifier wanted I find that I am being placed “on hold” when I phone a large number of organisations. Why not offer a small amplifier to rest your phone ear piece on to hear when the called number is back to you or better still, a complete hands-free amplifier and microphone to listen and talk while your hand phone rests on it? It could be mains or battery-powered and activated when the phone hand piece is placed on the unit and shut off when the phone is removed. (N. S., via email). •  Have you seen our Hands-Free Speakerphone design presented in the September 1988 issue? This could fit your needs. We can supply a photostat copy of the article for $7.70 including post­age & GST. A-V transmitter has poor range A while ago I bought an Audio/ Video Transmitter (described in July 1999) from Jaycar. I have finally got around to building it. I have two problems though, and hope you can help. After building the kit, I tested it using my DVD player. It works fine if I don’t take it any more than about 2-3 metres away! Any more than this and I start to lose the signal and get poor reception. I have tried adjusting the trimpots and still get the same re­sult. I have also tried to connect up a CCD camera using the power output and video input but get no results. I purchased the camera from Dick Smith Electronics and testing shows that the power is getting through and there is some sort of signal. Why won’t it work? (J. R., via email). •  Check that the 3-terminal regula- supply. Can you help me? Is there anything else about the clock that I need to change? (M. S., via email). •  The clock can be run using solar cells and a battery. The circuit will Solar power for draw a maximum of 400mA or 4.8W big digit clock at 12V. In low light, the display will I would like to power the Big Digit draw less current, dropping to around Clock (described in March 2001) from 100mA (1.2W) at night. So on average, a solar power supply. I need to know the clock will draw about 300mA the current and consumption of the (3.6W) depending on the length of 80x181mm.qxd 3/5/01 AM Page 1 clock in order to make 11:37 the power daylight hours. tors have not been trans­posed. We referred to this in Errata published in February 2001. The 5V regulator (7805) should be nearest to IC2 and the 12V regulator (7812) closest to diode D2. Check that you have these correct. There should be 12V available for the video camera. The transmission range does seem to be very poor. This suggests that one of the amplifiers, IC1 or IC2, is not working. This could be because one is connected incorrectly, an open-circuit connection to one of the pins or there is a short. Also check that the connection passing into the RCA socket for the modulator output (see the Jaycar notes on connecting the wire directly rather than using the plug) is not shorting to the case of the modulator. Plug the camera directly into your TV or VCR to check if it is working correctly, before trying to get it operational on the transmitter. Using Dr Video with NTSC signals Is the Dr Video stabiliser published in the April 2001 issue only applicable to PAL signals or is it universal? Specifi­cally, can I use it on my DVD player when outputting NTSC sign­als? (S. B, Wollongong, NSW). •  The timing for NTSC signals is close enough to PAL to allow the circuit to work fairly well. However, some of Meterman. The Working Man’s Meter. Meters that fit your job. Meters that fit your wallet. Introducing Meterman, a hot new brand of test and measurement tools that gives you the performance you need at a price you can afford. Meterman is a line of more than 60 meters, clamps, and testers. Each one designed with the right combination of features, functions and accuracy to fit your application. You work hard on the job. Get the tool that’s easy on your wallet. Ask your local test and measurement supplier for the Meterman products or contact Meterman on Locked Bag 5004 Baulkham Hills NSW 2153, phone 02 8853 8812 or fax 02 8850 3300, or visit metermantesttools.com TM July 2001  99 PIC NiMH charger wanted You recently published a NiCad battery charger for power tools (April 2001). How about a similar project for NiMH batter­ ies? The only difference I’d need is 12VDC input so I could use it in the car. I’d be using it to charge four AAs for my digicam while on holiday. (A. G., via email). •  There should be no reason to change the design at all apart from a change to the 3.3kΩ sensing resistor the latest NTSC releases on DVD have an ‘improved’ version of Macrovision which isn’t easy to remove. So the results on these DVDs may be disap­ pointing. Where to get BASIC •  We occasionally get queries about where to get BASIC for use with various past projects. As some readers may be aware, GWBA­ SIC/QBASIC interpreters were supplied free until DOS version 6. The original IBM PC even had a ROM-based interpreter (BASICA). We’ve had a good look at what’s available and can thorough­ ly recommend FirstBASIC, available as shareware ($US25 to reg­ister) from http://www.powerbasic.com You’ll find it listed on their down­ loads page. FM SCA decoder/multiplexer I was wondering if you have ever published a design for a circuit to to cope with the lower voltage from your battery pack. However, we are not certain whether the PIC’s code has the resolution to cope with the re­ quired dV/dt end-of-charge detection. NiMH cells have a very similar charge profile to NiCads but they peak at around 1.8V. You need to be aware also of the C value and note that NiMH cells like to be charged slightly below 1C (about 90%). If the batteries are around 1450mAH then 1Ω should be OK for the current limiting resistor. decode the SCA (subcarrier auxiliary) channels that are transmitted by some of the FM broadcasters. I am not really interested in using it for this purpose, but I want to build a multiplex system designed around the same principle. I have several wideband (100kHz) radio links that I want to feed to up to six narrow-band (0 to 3.5kHz, phone quality) audio channels. I thought that by modulating subcarriers, as they do with SCA, I could achieve the results that I want. I planned to use subcarriers at, 25kHz, 35kHz, 45kHz, 55kHz and so on. (P. D., via email). •  We published an ACS Adaptor (same thing as SCA) in the January 1988 issue. We can supply a photostat copy of the article for $7.70 including postage. Charging circuit for a strobe lamp I am trying to solve a puzzle, on how to charge a 680µF capacitor quickly, up to 320-340V DC, suitable for a highspeed disco strobe. The existing circuit is an AC-to-DC convert­er, which then steps it up to 500V DC using a Mosfet WARNING! and an inductor. It’s way too slow and inefficient. I know that by using a high-voltage diode and some sort of current limiting device, you can charge a capacitor to 320V from the 240VAC mains supply. I have experimented with various devices to achieve this, from a fluorescent light ballast to a light bulb to resistors and even winding my own inductor. I need this circuit to repeatedly charge this capacitor quickly, providing the 320V DC needed to fire the large Xenon bulb of the strobe. The trigger circuit etc is the easy part which I can do myself. (J. W., via email). •  How fast do you want the strobe to be? We published a beat-triggered strobe in the August 1998 issue which would run at up to 20 flashes per second. Anything faster tends to be perceived as continuous light so there is not much point. Our design used two 470Ω 5W resistors in series with a bridge rectifier running directly from 240VAC. It is quite fast enough and if you use higher charge currents and faster flash rates the limiting factor becomes the ripple current ratings on the discharge capacitor. We can supply the August 1998 issue for $7.70 including postage. Notes and Errata Parallel Port PIC Programmer and Checkerboard, March 2001: the circuit diagram on page 64 indicates that IC1 is an inverter. In fact, IC1 is a 7407 hex buffer with open-collector outputs. These buffers do not invert from input to output. Some kits for this project have been supplied with a female D socket and “gender changer”. This will not work. The specified male D socket must be SC used. SILICON CHIP magazine regularly describes projects which employ a mains power supply or produce high voltage. All such projects should be considered dangerous or even lethal if not used safely. Readers are warned that high voltage wiring should be carried out according to the instructions in the articles. When working on these projects use extreme care to ensure that you do not accidentally come into contact with mains AC voltages or high voltage DC. If you are not confident about working with projects employing mains voltages or other high voltages, you are advised not to attempt work on them. Silicon Chip Publications Pty Ltd disclaims any liability for damages should anyone be killed or injured while working on a project or circuit described in any issue of SILICON CHIP magazine. Devices or circuits described in SILICON CHIP may be covered by patents. SILICON CHIP disclaims any liability for the infringement of such patents by the manufacturing or selling of any such equipment. SILICON CHIP also disclaims any liability for projects which are used in such a way as to infringe relevant government regulations and by-laws. Advertisers are warned that they are responsible for the content of all advertisements and that they must conform to the Trade Practices Act 1974 or as subsequently amended and to any governmental regulations which are applicable. 100  Silicon Chip REFERENCE BOOKSHOP GREAT BOOKS FOR ENQUIRING MINDS! AUDIO POWER AMP DESIGN HANDBOOK AUDIO ELECTRONICS By John Linsley Hood. From one of the world’s most respected audio authorities. The new 2nd edition is even more comprehensive, includes sections on load-invariant power amps, distortion residuals and diagnosis of amplifier problems, and much more. 368 pages in paperback. This book is for anyone involved in designing, adapting and using analog and digital audio equipment. It covers tape recording, tuners and radio receivers, preamplifiers, voltage amplifiers, audio power amplifiers, compact disc technology and digital audio, test and measurement, loudspeaker crossover systems, power supplies and noise reduction systems. 375 pages in soft cover. By Douglas Self. 2nd Edition Published 2000 $ 85 First published 1995. Second edition 1999. EMC FOR PRODUCT DESIGNERS THE CIRCUIT DESIGNER’S COMPANION By Tim Williams. First pub­­lished 1992. 3rd edition 2000. Widely regarded as the standard text on EMC, this book provides all the information necessary to meet the requirements of the EMC Directive. It includes chapters on standards, measurement techniques and design principles, including layout and grounding, digital and analog circuit design, filtering and shielding and interference sources. The four appendices give a design checklist and include useful tables, data and formulae. 299 pages, in soft cover. By Tim Williams. First published 1991  (reprinted 1997). 99 $ $ UNDERSTANDING TELEPHONE ELECTRONICS By Stephen J. Bigelow. Third edition published 1997 $ 59 A very useful text for anyone wanting to become familiar with the basics of telephone technology. The 10 chapters explore telephone fundamentals, speech signal processing, telephone line interfacing, tone and pulse generation, ringers, digital transmission techniques (modems & fax modems) and much more. Ideal for students. 367 pages, in soft cover. 65 By Austin Hughes. Second edition published 1993 (reprinted 1997). For non-specialist users – explores most of the widely-used modern types of motor and drive, including conventional and brushless DC, induction, stepping, synchronous and reluctance motors. 339 pages, in paperback. DIGITAL ELECTRONICS – A PRACTICAL APPROACH H E R E P&P 65 $ By Richard Monk. Published 1998. By Eugene Trundle. First pub­­lished 1988. Second edition 1996. Eugene Trundle has written for many years in Television magazine and his latest book is right up to date on TV and video technology. The book includes both theory and practical servicing information and is ideal for both students and technicians. 382 pages, in paperback. Includes grounding, printed circuit design and layout, the characteristics of practical active and passive components, cables, linear ICs, logic circuits and their interfaces, power supplies, electromagnetic compatibility, safety and thermal management. 302 pages, in paperback. 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TAX INVOICE Your Name__________________________________________________________ PLEASE PRINT Address ____________________________________________________________ ___________________________________ Postcode_______________ Daytime Phone No. (______) __________________________________ STD  GUIDE TO TV & VIDEO TECHNOLOGY............................$59.00  Cheque/Money Order enclosed  THE CIRCUIT DESIGNER'S COMPANION........................$65.00  Charge my credit card   –    Bankcard   Visa Card   MasterCard  UNDERSTANDING TELEPHONE ELECTRONICS.................$65.00                BOOK TOTAL: $...................... PLUS P&P (if applic): $................... ORDER TOTAL$ AU................ Orders over $100 P&P free in Australia. AUST: Add $A5.50 per book NZ: Add $A10 per book, $A15 elsewhere OR No: Signature______________________Card expiry date POST TO: SILICON CHIP Publications, PO Box 139, Collaroy NSW, Australia 2097. OR CALL (02) 9979 5644 & quote your credit card details; or FAX TO (02) 9979 6503 ALL TITLES SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES INCLUDE GST MARKET CENTRE Cash in your surplus gear. Advertise it here in Silicon Chip. FRWEEBE YES! Place your classified advertisement in SILICON CHIP Market Centre and your advert will also appear FREE in the Classifieds-on-the-Web page of the SILICON CHIP website, www.siliconchip.com.au And if you include an email address or your website URL in you classified advert, the links will be LIVE in your classified-on-the-web! S! D E I F I S C LAS EXCLUSIVE TO SILICON CHIP! CLASSIFIED ADVERTISING RATES Advertising rates for this page: Classified ads: $11.00 (incl. GST) for up to 12 words plus 55 cents for each additional word. Display ads: $27.50 (incl. GST) per column centimetre (max. 10cm). Closing date: five weeks prior to month of sale. To run your classified ad, print it clearly in the space below or on a separate sheet of paper, fill out the form & send it with your cheque or credit card details to: Silicon Chip Classifieds, PO Box 139, Collaroy, NSW 2097. Or fax the details to (02) 9979 6503. Taxation Invoice ABN 49 003 205 490 _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ Enclosed is my cheque/money order for $­__________ or please debit my ❏ Bankcard   ❏ Visa Card   ❏ Master Card Card No. Signature­­­­­­­­­­­­ ________________________  Card expiry date______/______ Name _____________________________________________________ Street _____________________________________________________ Suburb/town _________________________  Postcode______________ 102  Silicon Chip FOR SALE BLEMISH FREE & LOW BLEMISH CCDs * UP TO 5 YEARS WARRANTY * OVERNIGHT DELIVERY * PC DIGITAL VIDEO RECORDER - Alarm Inputs & Outputs - Dial-In Remote Viewing – Auto Dial-Out to Pagers – Telephones – PC – WWW from $599 * VCR Controller use a home VCR for Surveillance Event Recording Wireless IR Control only $39 * EXTRA High 600 + H-Line Modules – Domes – Covert in PIR Case with SONY Super HAD CCD & SONY Chipset from $122 * Mini Cameras from $61 COLOUR from $85 * TIME LAPSE 24 hour VCRs from $599 National Service Centers * Multinational Manufacturer ! * QUAD 1024 H-Pixels from $175 * COLOUR QUAD only ! $389 * DOME VIDEO CAMERAS from $53 ! 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Dunfield C Compilers: Everything you need to develop C and ASM software for 68HC08, 6809, 68HC11, 68HC12, 68HC16, 8051/52, 8080/85, 8086, 8096 or AVR: $198 each. Demo disk available. ImageCraft C Compilers: 32-bit Windows IDE and compiler. For AVR, 68HC11, 68HC12. $396. Atmel Flash CPU Programmer: Handles the 89Cx051, 89C5x, 89Sxx in both DIP and PLCC44 and some AVR’s, most 8-pin EEPROMS. Includes socket for serial ISP cable. $220, $11 p&p. SOIC adaptors: 20 pin $99, 14 pin $93.50, 8 pin $88. Full details on web site. Credit cards accepted. GRANTRONICS PTY LTD, PO Box 275, Wentworthville 2145. (02) 9896 7150 or http://www.grantronics.com.au HOME CCTV Mono / Colour PAKS only ! $119 / $151 Full DIY Plug-In to TV / VCR 20 metre Cable, Plug Pack & Camera www.allthings.com.au DIGITAL OSCILLOSCOPE kit. www.ar.com.au/~softmark RCS HAS MOVED to 41 Arlewis St, Chester Hill 2162 and is now open, with full production. Tel (02) 9738 0330; ROLA AUSTRALIA PH/FAX (08) 8270 3175   WEB SITE WWW.BETTANET.NET.AU/GTD Model Flight Control Modules CHECK OUR WEBSITE FOR DETAILS ON KITS AND COMPONENTS •  TRANSMITTER KITS AND MODULES •  AUDIO MODULES •  COMPUTER INTERFACE KITS •  RADIO STATION AUDIO SOFTWARE NEW: Our MP3-CD player in short form for $169 inc GST. Includes the following: processor board, front panel display and tactile keypad; just add a case, cables, 12V power supply and a CD-ROM drive. Play CDs and up to 2600 MP3’s from a CDR. Great for car or home. Satellite TV Reception International satellite TV reception in your home is now affordable. Send for your free info pack containing equipment catalog, satellite lists, etc or call for appointment to view. We can display all satellites from 76.5° to 180°. AV-COMM P/L, 24/9 Powells Rd, Brookvale, NSW 2100. Tel: 02 9939 4377 or 9939 4378. Fax: 9939 4376; www.avcomm.com.au PDC 01 SERIAL INTERFACE $198.60 PDC 10 GPS INTERFACE MODULE $398.00 PDC 20 ALTITUDE HOLD MODULE $498.00 PDC25 SPEED HOLD MODULE $498.00 PDC 400 ALTIMETER AIR-DATA SENSOR $398.40 PDC 450 AIRSPEED-AIR DATA SENSOR $398.00 PDC1200 VIDEO OVERLAY (PAL-D) $698.60 TRACKER GPS TELEMETRY SOFTWARE $198.60 PDC 3200 AUTOPILOT AND GROUNDSTATION: PRICE ON APPLICATION (PRICE DEPENDS ON CONFIGURATION). (ALL PRICES INCLUDE GST) Silvertone Electronics, PO Box 580, Riverwood 2210. Phone/Fax (02) 9533 3517. www.silvertone.com.au Positions At Jaycar We are often looking for enthusiastic staff for positions in our retail stores and head office at Silverwater in Sydney. A genuine interest in electronics is a necessity. Phone 02 9741 8555 for current vacancies. Fax 9738 0334. rcsradio<at>cia.com.au; www.cia.com.au/rcsradio DIY CCTV PAKS 4 Cameras & Switcher .................$354 as above COLOUR ......................$466 4 Cams, Switcher/Monitor ...........$495 4 Cams & QUAD .........................$478 4 COLOUR & QUAD ....................$752 Time-Lapse 24 hr VCR only $599 with CCTV Systems! MORE at: www.allthings.com.au Fully Plug-In DIY Paks with Cables & Power Supplies * PC W98/W2000 Digital Motion/Sound detection & activat­ed Video/Audio Recording systems. PCBs MADE, ONE OR MANY. Low prices, hobbyists welcome. Sesame Elec­tronics (02) 9586 4771. sesame<at>internetezy.com.au; http:// members.tripod.com/~sesame_elec VIDEO amplifiers, Stabilisers, TBCs, Converters, Mixers, etc. QUESTRONIX (02) 9477 3596. FREE DELIVERY, new release colour Need prototype PC boards? We have the solutions – we print electronics! Four-day turnaround, less if urgent; Artwork from your own positive or file; Through hole plating; Prompt postal service; 29 years technical experience; Inexpensive; Superb quality. Printed Electronics, 12A Aristoc Rd, Glen Waverley, Vic 3150. Phone: (03) 9545 3722; Fax: (03) 9545 3561 Call Mike Lynch and check us out! We are the best for low cost, small runs. dome camera pan/tilt via remote control. Only $790. Colour camera 600+ lines $99. Wireless audio-video transmitter $65. Bug 1.2km $59. BUY DIRECT AND SAVE. GCS: 0410 739 317 OR (02) 4227 9933. KIT ASSEMBLY NEVILLE WALKER KIT ASSEMBLY & REPAIR: · Australia wide service · Small production runs · Specialist “one-off” applications Phone Neville Walker (07) 3857 2752 Email flashdog<at>optusnet.com.au continued next page July 2001  103 DON’T MISS THE ’BUS Advertising Index Altronics................................. 78-80 Aust. Video Systems....................65 Allthings Sales & Services..102,103 Av-Comm Pty Ltd.......................103 Do you feel left behind by the latest advances in com­puter technology? Don’t miss the bus: get the ’bus! Includes articles on troubleshooting your PC, installing and setting up computer networks, hard disk drive upgrades, clean installing Windows 98, CPU upgrades, a basic introduction to Linux plus much more. Control Devices.........................IFC Dick Smith Electronics........... 24-27 Emona.......................................IBC Evatco..........................................95 Grantronics................................103 Harbuch Electronics....................88 Price: $12.50 (incl. GST) Order now by using the handy order form in this issue or call (02) 9979 5644, 8.30-5.30 Mon-Fri with your credit card details. Special subscription offer available only while stocks last. Silicon Chip Binders   Each binder holds up to 14 issues   Heavy board covers with 2-tone green vinyl covering   SILICON CHIP logo printed in gold-coloured lettering on spine & cover Instant PCBs..............................103 Jaycar ................................... 49-56 Kalex............................................95 REAL VALUE AT $12.95 PLUS P & P Mass Technologies Pty Ltd..........89 Meterman....................................99 MicroZed Computers...................89 Microgram Computers........13,OBC Oatley Electronics........................42 Price: $A12.95 plus $A5.50 p&p each (Australia only; not available elsewhere). Buy five and get them postage free. Printed Electronics.................... 103 Just fill in & mail the handy order form in this issue; or fax (02) 9979 6503; or ring (02) 9979 5644 & quote your credit card number. RCS Radio.................................103 Questronix............................89,103 RF Probes...................................89 RobotOz......................................89 WANTED SERVICE MANUAL or circuit diagram for Technics classical organ model SX 103F. Email icc<at>powerup.com.au Tel 07 3376 4409. PERSON WITH EXPERIENCE/APTITUDE to fault find & repair PCBs – without diagrams. GENEROUS PKG NEG. Tel John<at>AER (03) 9482 4958 or 0415 305 470. Circuit Ideas Wanted Do you have a good circuit idea? If so, sketch it out, write a brief description of its operation & send it to us. Provided your idea is workable & original, we’ll publish it in Circuit Notebook & you’ll make some money. We pay up to $60 for a good circuit so send your idea to: Silicon Chip Publications, PO Box 139, Collaroy, 2097. HELP SAVE THE NIGHT SKY! We are losing our heritage of starry night skies. Poor, inefficient outdoor lighting is causing glare and “light pollution”. This wastes energy and increases greenhouse gas emissions. You can help by joining SYDNEY OUTDOOR LIGHTING IMPROVEMENT SOCIETY (SOLIS). SOLIS aims to educate and inform about quality outdoor lighting and its benefits. We also lobby councils, government and other bodies to promote good lighting practice. SOLIS meetings are held third Monday night of each month at Sydney Observatory. Individual membership is $20 pa. Donations are also welcome. Cheques payable to “SOLIS c/- NSAS”, PO Box 214, West Ryde 2114. Email: tpeters<at>pip.elm.mq.edu.au 104  Silicon Chip Rola Australia............................103 R.T.N............................................48 Semtron Electronics....................41 Silicon Chip Back Issues....... 96-97 Silicon Chip Binders..................104 Silicon Chip Bookshop...............101 SC Computer Omnibus.............104 Silicon Chip Subscriptions...........57 Silvertone Electronics................103 Smart Fastchargers.....................41 Solar Flair/Ecowatch..................102 ___________________________ PC Boards Printed circuit boards for SILICON CHIP projects are made by: •  RCS Radio Pty Ltd. Phone (02) 9738 0330. Fax (02) 9738 0334. SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.tek.com