Automating PC Power-Up

In the June 2004 edition of SILICON CHIP, page 77, you had a small item on how to modify your ATX type PC motherboard to start up on applying the power, rather than by the front case ON/OFF button.

It’s even easier than that for almost all ATX motherboards. Every ATX motherboard that I’ve seen/used has an option in the BIOS to have the PC start when power is applied. In my rather outdated ASUS A7V motherboard BIOS it appears under Power
->Power Up Control->AC PWR Loss Restart from which I have a choice of "Disabled" [Default] , "Enabled" or "Previous State". In my more current EPOX 8RDA+, it appears in the BIOS as Integrated Peripherals->PWRON After PWR-Fail, with the choice of "Disabled" [Default] , "Enabled" or "Previous Status".

You only need to set it to "Enabled", save the BIOS settings and from then on, every time power is applied, the PC will start booting.

It only takes a little reasoning to realise that this is probably available in all ATX BIOS’; eg, wouldn’t you want a PC that’s doing critical data logging/process monitoring to be up and continuing its operations as soon as power is restored after failure?

Dave Clarke,
via email.

Comment: we thought of this at the time. What you’re saying makes sense but the motherboards we checked did not have this option.

More praise for vintage Tektronix scopes

Over recent months there have been a number of references to vintage Tektronix CROs in these columns. My familiarity with the breed goes back the early 1970s and in particular, the model 564B with storage facilities. The term "built like a battleship" certainly applies to that generation.

The build quality was something that one rarely sees today with the plethora of ASICs, multi-layer printed circuits and plastic everything. There wasn’t an IC to be seen. Instead, it had a mixture of discrete transistors (and the then quite new tunnel diode) and glass valves, including one of the last hurrahs of the valve era, the Nuvistor.

However, with all those discrete components, over their long lives they did need "fixing" from time to time. I have a lengthy list of repairs carried out to my model over its lifetime (it is still here and working as well as ever) and wondered if some out there are familiar with the fact that the vertical and horizontal "plug-ins" can be safely interchanged’ ie, fit the vertical amplifier in the right bay and vice-versa.

This is a great help when diagnosing faults dynamically, as it allows access to the component side of each chassis. Of course, the trace becomes vertical instead of horizontal but otherwise everything works as normal. The only exception that I am aware of is that the trace brightening signal for the delayed scan is not picked up in the left bay.

Brian Critchley,
via email.

PC board design hint for creating Postscript file

Your PC Board Design tutorial has been an invaluable resource to me. However, I would like to point out that in Pt.3, there is a small omission that may cause readers some difficulty. When creating a postscript file with Traxplot, the Postscript Setup default value for Quality is "Draft".

You must change this to "Final Artwork" or your resulting file will appear as line art instead of solid tracks, pads and components. Thanks again for your fine series of articles.

Mako Natsume,
via email.

Impressive designb in ESR meter

I am writing to congratulate you on the magazine. I have read every Oz electronics magazine since 1940, with a few gaps during WW2. SILICON CHIP is as good as any of them.

Thank the developer of the ESR meter. I have just finished building one and am very impressed with its design and abilities.

Tony O’Brien, VK2BOA,
via email.

Unnecessary warnings discourage initiative

SILICON CHIP magazine seems to come up with one excellent project after another. I am particularly grateful for the "Energy Meter" project in the July and August 2004 issues and will be building a number of these. However, I object to the caution on page 38 of the July 2004 issue, in relation to viewing waveforms of the Energy Meter circuit.

Surely SILICON CHIP realises that there are a significant proportion of its readers who could safely connect their scopes to this circuit. Why then, have a warning that applies only to completely inexperienced hobbyists. Such a warning actually deters those hobbyists from learning how such oscilloscope viewing could be safely accomplished? Have lawyers and insurance companies really screwed up our society to that extent?

Every day, all over Australia, many electrical and electronics engineers, technicians and hobbyists are connecting monitoring instruments to circuits at mains potential. I am convinced that anyone who has a suitable scope probe and has sufficient knowledge to use it could safely monitor the waveforms in the Energy Meter circuit.

The most common suitable probe would be a passive 100x probe with a voltage rating of 1kV or more. I have two of these and use them regularly. One of these is an ETM 2101, a low-cost 100x probe rated at 1.2kV which I have owned for 15 years. The other probe is a Tektronix P5100, a 100x probe rated at 2.5kV (purchased as new on eBay for US$160, with freight from the US an extra US$9, making a total of approximately $240 Australian).

Other suitable but less common probes are high voltage differential probes, such as the superb (but pricey) Tektronix P5205. The advantage of a differential probe is that "floating" measurements can also be made using only one channel of a scope. However, with two suitable 100x passive probes and a 2-channel scope in differential mode, such mains level floating measurements can be made much more cheaply.

The Energy Meter circuitry is referenced to Neutral and I am convinced that a suitable 100x passive scope probe could be used safely by a relative novice to view at least some of its mains voltage waveforms using only one channel of an oscilloscope. One simply uses the "witches hat" probe accessory on the probe tip and hooks this to the desired test point BEFORE applying power to the circuit (but first remove the accessory grounding cable if it is connected to the probe tip). Of course, the power would need to be turned off again BEFORE disconnecting the probe.

I find it extremely difficult to believe that even a novice would get into trouble if they followed this procedure. I am convinced that relatively inexperienced electronics hobbyists are entitled to "learn how to do it properly", even if they have no intention of pursuing formal qualifications in electronics.

If we continue to succumb to the "electricity is voodoo" garbage promoted by vested interests such as the electricians’ lobby and their allies in the insurance sectors, we will surely kill off knowledge and initiative.

Otto S. Hoolhorst,
Brisbane, Qld.

Comment: we still think the warning is a good idea. The Publisher’s Letter on page 2 has further details.

Big cooler envy

I have recently spent a great deal of time trying to find a way of making my computer system quiet. I noticed your July 2004 issue had an article on how to silence a screaming computer. I was impressed by the Zalman "Reserator" system which I promptly purchased from my local computer store.

I was almost overwhelmed with the size of my Reserator (600mm) but on re-reading your article (600m) this gave me a feeling of inadequacy and I was tempted to ask my supplier for the same model you have acquired. In the meantime, I humour myself by putting a "hazmat" sticker on it and telling friends I have a nuclear-powered computer.

Garry Surplice,
Campbelltown, NSW.

Comment: sorry you feel inadequate. It is just that computers and coolers for SILICON CHIP magazine need to be much bigger so we got a 600m unit. It is quite imposing and does need aircraft warning lights and very big foundations but we have found it very effective at cooling. So effective in fact that we have experienced climate change in the whole Northern Beaches area.

We are thinking of turning it into a local tourist attraction, with rides, bungee jumping, etc.

Short life from CFLs

I couldn’t agree more with Leo Simpson’s write-up in the August 2004 issue on compact fluorescent lights. We have seven of these globes in our house and so far we have replaced four of them within six months of installing them as brand new units. This is not good enough. Or is it is a conspiracy by these companies so they make bigger and bigger profits at our expense?

If so, we should all go back to the incandescent globe until they get it right.

Russell & Kerin Sharp,
Morphett Vale, SA.

Long life from CFLs

I read with absolute amazement your editorial on compact fluorescents (August 2004 issue). In my experience, their life is "as advertised". I live in a townhouse and I purchase globes for outside lighting on behalf of the Body Corporate. More than 10 years ago, we installed four CFLs under the carports (ie, sheltered from the weather) and these are on from dusk until dawn every day.

Over the year, this would probably average about 10 hours per day. To keep track of the life, I mark the installation date on the base of the lamp. At the moment, we have one which has been in use since July 2002 and it is still working fine.

This is normal; I don’t expect anything less than two years from them, which works out at more than 7000 hours. The main brands that we use are Philips and GE.

What is happening in Sydney? Maybe your electricity supply is very bad. Perhaps you should monitor it for a while to see just what voltage fluctuations, spikes, etc are occurring.

David Bramwell,
Melbourne, Vic.

PC boards from negative-acting resist

Further to the letter by Geoff Thomas in the June 2004 issue, I offer the following suggestions for producing boards of the same quality as Geoff alluded to but even cheaper, using standard LaserJet transparency film.

The first is to use negative-acting PC board material in place of positive. In this case, tracks correspond with clear artwork areas, so the sieve-like quality of artwork derived from standard transparency film does not compromise the integrity of tracks. The only possible (and obviously undesirable) effect is to leave unwanted copper in gap areas, leading to bridging.

This is averted by lightly brushing the PC board with a 2-inch paintbrush to physically assist resist removal during development under subdued yellow light. This does not remove fine tracks, once optimum conditions of exposure, development and developer temperature have been established.

Another advantage with negative-acting resist is that artwork may be drawn with very small gaps between tracks, because the width of gaps increases during exposure and development. The reverse is true of positive-acting material. That is, bridging occurs if gaps are drawn too small. I have never had a problem drawing 0.00325" gaps under vacuum exposure.

The only real downside to the negative-acting material I use is that it is covered by a thin transparent Mylar protective film, causing handling and cutting difficulties. A guillotine is best for cutting it to size.

On the upside, it can be developed safely, quickly and at negligible cost using dilute sodium carbonate solution. Also, the clear Mylar forms a barrier between artwork and resist, negating the possibility of sticking under high vacuum exposure. As part sheets of transparency film may be recycled through the LaserJet, the materials cost per small project artwork and development is around $0.40.

What is more, once experiment has yielded optimum exposure and development conditions, it works first time every time, with the potential to produce project artwork of such fineness that the home constructor could not reliably solder components to the resulting PC board.

Ross Metcalf,
via email.

Hifi power cords and other Kozmic bunk

I agree with David Collins (Mailbag, July 2004) that the scientific paradigm requires testing a hypothesis. However, the hypothesis in this case is that a different power cord will make an amplifier sound different, not Leo Simpson’s quite unexceptional assertion that it won’t.

David is only a little bit pregnant in demanding rigour. There are some other philosophical rules of reasoning that must be applied also. The first is that it is impossible to prove a negative. One test can show it does have an effect but only an infinite number of tests can show it doesn’t. And while the tests proceed, the carpetbaggers continue to fleece the sheep.

I’m sure that Golden Ears will assert that they can hear a difference. But this is totally unscientific anecdote, only a possible starting point for an investigation using double-blind crossover techniques and not a triumphant QED.

The second, and in this case more to the point, is that extraordinary claims require extraordinary proof. Many of the claims made for hifi systems and accessories are so extraordinary as to be absurd, and like assertions of a flat Earth and perpetual motion, can be safely rejected out of hand.

There is also the paradox of the frequent demand by "Hiper-Finatics" that critics rigorously follow scientific method, but who make wild and untestable claims based on nothing better than subjectivism operating somewhere outside long and well established theory.

David should save his concerns for the much more complex amplifier at the end of the lead which also operates "only theoretically". Without "only theory" he wouldn’t have an amplifier to worry about powering in the first place.

The snobbish egocentric entrenched ignorance and self-deception endemic in the world of so-called hifi ("my ears are better than your instruments") would only be sad were it not for the very considerable sums of money that change hands as a result, leading to outright fraud.

Roly Roper,
Ivanhoe, Vic.

Valve electronics not practical in the long term

I refer to the letter entitled "Valve Electronics Never Reached Its Peak" in the June 2004 issue. I cannot believe that anyone would think that vacuum tube technology could ever be a practical long-term system of electronics. Valves are cumbersome, power hungry, fragile and unreliable. What possesses your correspondent to think otherwise?

Don’t get me wrong; I love vacuum tubes. My first one-valve radio was nothing short of miraculous to me. I also remember reading about the invention of the transistor. I am surprised that the transistor was not stumbled upon by Graham Bell. I’ll bet that if he were more into physics than phonetics, this would have happened. I think that vacuum tubes were a natural stepping stone to solid-state electronics.

From my reading and observations, it appears that great ideas come as a result of the thinking of many. Sources of invention are the province of the prepared mind. How wonderful it would be to sit in the shed and invent wonderful things by some serendipitous process. Alas, the mental capacity, economic capability and stamina required to make major discoveries and the realisation of such discoveries now seems to be beyond the individual.

With this in mind I think that valves (vacuum tubes) did indeed reach their full potential. Solid-state technology is a further step along the continuum of scientific discovery.

Lionel Doolan,
Newcastle, NSW.

Valves are dinosaurs

I certainly don’t agree with Grahame MacPherson’s letter on valve technology versus the transistor. Valves in my opinion are dinosaurs, wasteful of energy, not nearly as robust, and expensive. The warmth of a valve amplifier is a myth and rates alongside the jumbo speaker cable hocus pocus.

I built my "Hikers One" valve radio as a boy back in 1951 and went on to build a superhet five, so I guess I cut my teeth on valve technology and enjoyed the experience. But the advent of the transistor and PC boards for the electronic enthusiast was a wonderful breakthrough as well as sheer joy.

Brian Gardner,
Kettering, Tas.

Video standards article is very useful

I must commend Jim Rowe for his excellent August 2004 article on "Video Formats: Why Bother?" I’m sure many readers would have gained from the concise explanations and clear photographs.

In the UK two years ago, my TV, VCR, hifi, etc, all interconnected seamlessly with the ubiquitous European standard 21-pin SCART connector, which I believe has separate RGB on pins 15, 11 & 7 respectively, with ground at pin 13; a very tidy and compatible solution!

Would it be sensible to embrace this standard in Australia? There are two objections perhaps: the standard is outdated by home entertainment system requirements; and the connectors are too large for cameras, laptops and digital video recorders. The latter can be solved with an S-video to SCART adapter. I used one to connect my Geforce 3 Ti300 video card to the TV.

Finally, a big thanks to SILICON CHIP. It is the finest electronics magazine I’ve seen world-wide. The print quality is second to none, the articles excellent and the advertising highly relevant.

Robert Gott,
Toowoomba, Qld.

Quiet PCs don’t need fans

I read your article on silencing PCs, in the July 2004 issue, with interest. Noisy PCs are not a new phenomenon – I recall using one of the early IBM PCs and it reminded me of a jet aeroplane taking off.

In your article, you focused exclusively on how to build a top-of-the-line system that did not require you to wear earmuffs. There is an alternative approach – start with a system that doesn’t need forced-air cooling.

VIA make a range of CPUs that don’t need active cooling. Whilst they are only in the 500-800MHz region, this is plenty fast enough for normal multi-media or office work. The power consumption is low enough that the power supply doesn’t need a fan either, so the only moving part is the disk drive. You can build a whole PC that needs less power than a top-end CPU.

For details see www.mini-itx.com. You can also buy them locally at www.traverse.com.au

Also, you mention cleaning the heatsink compound off when changing heatsinks. Some heatsink compounds include beryllium oxide – this is highly carcinogenic and you should be careful to avoid contact with it.

Peter Jeremy,
via email.

Comment: we agree that the VIA CPU is a valid approach – except that a lot of today’s software demands higher speed and performance.

Making solar power pay

I moved from Sydney to Adelaide a little while back. The combination of higher energy prices and lower housing prices led me to look at how I could use some of the cash I had left in my pocket to cut my utilities bills.

There were all the obvious things like replacing all the incandescent globes with compact fluorescents and replacing the curtains with ones that would reduce heat loss.

I had planned to do solar power too, feeding excess power generated back into the mains and turning the meter backwards, but when I looked at it closely I found that all the groups involved had, while saying that people should do it, gone out of their way to make it as difficult and uneconomic as possible.

Enough solar panels to generate 1kW under ideal conditions cost about $8000 and you get $4000 back from the government, leaving only $4000 to pay. But this is only if it’s all designed and approved and installed by people who manage to inflate that to about $11,000. That investment only generates about $275 worth of power a year, even at Adelaide’s prices.

It’s a better proposition to take your $11,000, invest it in a term deposit and pay your power bills out of the interest. It’s amazing that anyone does it.

How to get the power up? What about a system of stainless steel reflectors to produce an effective 40% increase in output. How to get the price down? There are things you can’t get the price down on, like having a qualified electrician do the mains side of the wiring. But other than the solar panels themselves, the big ticket component is the DC-to-240V 50Hz inverter that connects to the mains.

There’s nothing high-tech about it but there is only one product you can buy: Latronics PV Edge, costing about $3500. Its a good product but there has to be a cheaper way of doing it. Is a mains-connectable inverter a project that SILICON CHIP would do?

Gordon Drennan,
Burton, SA.

Comment: back in March 2002 we published an article debunking domestic solar power installations and noting that the "pay-back period" was around 20 years – far too long to be a sensible investment. We also suggested other more effective means by which people could cut their greenhouse emissions, such as buying a new car, fridge, dishwasher, etc.

We got a lot of flak for that article but as you have found, it is still correct. Nor do we think that improved focusing onto the panels or cheaper regulation circuits would change the basic economics by much.