Fullscreen HTML5Med Res (??MB)HTML4

SERVICEMAN'S LOG How friendly is “user friendly”? How friendly is “user friendly”? That question was prompted by recent cases of customer confusion, caused mainly by technologies that were supposedly designed to overcome user difficulties with earlier designs. One product that causes a great deal of user difficulty is the VCR. They’ve been around for many years now but a surprising percentage of users still have trouble programming the timer. They can manage to record a program if they are present when it is being broadcast but setting it up for a late night movie, or for a favourite sitcom that clashes with a dental appointment, is completely beyond them. As a result, one of the major features of the VCR – and for which they paid good money – is lost. Unfortunately, efforts to overcome these problems don’t always help. On the contrary, they often seem to make things worse. And on top of this, makers keep loading on more and more features, most of which will never be used anyway and which only add further confusion to the scene. Of course it is easy enough to sneer at “user ineptitude”. But is this fair? The average user doesn’t have a degree in electronics or even a smattering of the discipline. Nor should they have to. It is time we stopped building confusion into these appliances. What started all this? The sudden realisation that, as a serviceman, I am being called on more and more to Fig.1: this circuit shows the controller IC (IC001) in the Sony KV-2183AS colour TV set. This receives instructions from the IF unit (IF201) via pins 10 & 11 (AFTD, AFTU). solve problems which don’t involve any mechanical or electronic failure. In­ stead, they are simply problems caused by user confusion. The largest area where these problems occur involves chan­nel selection and remote control. Let’s look at a couple of typical cases. The first one involved a Sony TV set, a KV-2183AS, owned by one of my lady customers. Her complaint was that, since her grandson had come to stay with her she couldn’t receive channel 9 any more and when she tried to restore it, she lost channel 7 as well. The Sony, like most modern sets, uses an automatic search system to set it up for the wanted channels. The user puts it into the search mode and it scans the band(s) until it finds a channel. The user then has the option of putting that channel into memory or bypassing it. Either way, the system then scans for the next channel and presents the same option. This procedure is repeated until all the wanted channels have been memorised and are ready to be recalled at the touch of a button. Willie did it Well, there are no prizes for guessing what had happened in this case and the lady had been honest enough to admit to it, which is more than I can say for some customers. Little Willie had had a bit of a fiddle and made a mess of things. Anyway, I didn’t imagine it would be anything more than a routine job. How wrong can you be! I pressed the programming buttons and the system went into search mode. But, instead of stopping as it reached each channel, it shot straight through and just kept on searching, repeatedly going around and around through all the bands. However, in a seeming contradiction, the remaining channels – 2, 10 and SBS) were still locked in mem­ory and could be called up. I wasn’t quite sure where to start, a November 1995  69 Fig.2: the IF unit in the Sony KV-2183AS drives the controller IC (IC001) from pins 5 (AFT DN) and 4 (AFT UP). factor not helped by the fact that access to the appropriate PC boards leaves a lot to be desired. But the circuit suggested two suspects: (1) the con­troller IC (IC001 – M50431-611SP), which controls most of the set’s operational functions; and (2) the IF board (IF201 – IFB-368), which supplies some of the information to the controller. I picked the IF board as my first choice, if only because it was the easier option. The controller IC is a 42-pin device, whereas the IF board has only 12 pins. But, more than that, the IC was a relatively low risk device, while this IF board has something of a reputation. The complete assembly, in a metal can, carries a Mitsumi brandname and is used in several makes of sets. No circuit is available and it is described as being non-serviceable. Three of its terminals – 4 (AFT UP), 5 (AFT-DN) and 1 (RF AGC) – feed data to the controller. The works consist of a small PC board carrying an IC, coils, ceramic filters and some transistors. And the reputation, as you might have guessed, is for dry joints. Well, at least that aspect of it is serviceable, so I pulled it out and examined it. There were several obvious dry joints around the filters, which I fixed first. I then reworked the rest of the board. After all, once you get that far, there’s not much point in mucking about. Having done that, I refitted it and tried again. And that was it; it worked perfectly, stopping at every station. I repro­grammed it for the missing channels and the job was done. So everyone was happy. Well, more or less. While the lady was happy to have the set going again, it had cost her a service call and she must have wished that Little Willie had kept his fingers to himself. I hope the error of his ways was pointed out to him. OK, so there was a genuine technical failure, although it wouldn’t have mattered if Little Willie had left things alone. But the episode shows that making it easy to select and store channels can make it just as easy, or even easier, to foul things up. Remember the turret tuners in the early TV sets? The user couldn’t muck about with those. Granted, they were expensive and mechanically vulnerable and nobody really mourned their replace­ment with electronic tuning. But I wonder if the electronic systems could be made a bit more secure? The complicated NAD That Sony episode was really just a minor hiccup compared with the next story, which occurred shortly afterwards. The customer was a Greek gentleman who, unfortunately, had only a limited command of English. Even so, his command of English was far better than my command of Greek. Which made communication somewhat difficult. And we needed all the communications skills we could muster because his problem was a difficult one – a lot more difficult than he realised, in fact. However, with patience, the story eventually evolved. It transpired that he had purchased a NAD stereo TV set and VCR in a knockdown/job-lot deal from a highly respected company that was closing down after 30 odd years trading in Australia. And he wanted me to come around to his house and sort out some problems. 70  Silicon Chip In greater detail, the TV set was a NAD Monitor, which is really a rebadged ITT-Nokia 7163VT. These sets are made by Nokia Consumer Electronics, a very large Finnish company, which also makes sets under the Akai, ITT, Luxor and Salora labels. They also make mobile telephones and other electronic appliances. So what did I have to sort out? There were two problems really. One was that the set had been programmed for some sta­tions but not all, and the owner had no idea of how to go about doing this job himself. The other problem was harder to pin down initially but, by gestures, he indicated that the top of the picture was flicking back and forth; ie, flag-waving. However, this apparently only occurred when the set was working from a VCR, an important point as it turned out. My experience with European sets in general, and the Nokia family in particular, has been strictly limited; little more than secondhand from colleagues. But I had learned enough to know that they can be significantly different from the American and Asian designs with which we are most familiar. I was also aware that this was an upmarket model, featuring a whole host of features, But just how many I wasn’t to realise fully until much later. In fact, it is a multi-standard type –PAL, SECAM, NTSC – with provision for all the minor variations of these standards which occur from country to country. It also features stereo sound/dual language facilities (again with variations to suit different standards), digital sound (NICAM), Videotext and Teletext (with a wide range of options). And, in addition to the usual video recorder facili­ties, it can also handle a video disc player, video games, a pay TV decoder, a video camera, a computer and tape recorders. And so on. No instruction book Of course, the owner didn’t have an instruction book and that settled it; there was no way I was going to tackle a problem like that in-house. From what little I do know about European sets, I can’t escape the impression that, if there is a hard way to do something, they’ll find it. Anyway, I managed to explain that he would have to bring the set to the shop and that I might need it for some time. And so it eventually landed on my bench. But where should I start? There were no controls on the set, as everything was done via the control unit. And it was a control unit the like of which I had never seen before, though I’d previously heard about it. It is called a “TV Mouse” control – a supposedly impressive term obviously derived from the computer scene. So the first thing I had to do was learn how to use this device. My knowledge of mouses – er, these devices – is limited but I imagined there would be a ball on the underside, the kind of thing that is used to move a cursor around a computer screen. But there was nothing like this; it looked like a fairly standard control unit, though with a lot more buttons than most. The accompanying drawing will give the reader some idea (I only acquired this diagram much later). OK, let’s suppose I could work out how to use it. This should allow me to program in all the local channels and solve that problem. But what about the flag waving? In the normal way of things, flag waving suggests a fault in the ANOTHER GREAT DEAL FROM MACSERVICE 100MHz Tektronix 465M Oscilloscope 2-Channel, Delayed Timebase VERTICAL SYSTEM Bandwidth & Rise Time: DC to 100MHz (-3dB) and 3.5ns or less for DC coupling and -15°C to +55°C. Bandwidth Limit Mode: Bandwidth limited to 20MHz. Deflection Factor: 5mV/div to 5V/div in 10 steps (1-2-5 sequence). DC accuracy: ±2% 0-40°C; ±3% -15-0°C, 40-55°C. Uncalibrated, continuously variable between settings, and to at least 12.5V/div. Common-Mode Rejection Ratio: 25:1 to 10MHz; 10:1 from 10-50MHz, 6cm sinewave. (ADD Mode with Ch 2 inverted.) Display Modes: Ch 1, Ch 2 (normal or inverted), alternate, chopped (250kHz rate), added, X-Y. Input R and C: 1MΩ ±2%; approx 20pF. Max Input Voltage: DC or AC coupled ±250VDC + peak AC at 50kHz, derated above 50KHz. HORIZONTAL DEFLECTION Timebase A: 0.5s/div to 0.05µs/div in 22 steps (1-2-5 sequence). X10 mag extends fastest sweep rate to 5ns/div. Timebase B: 50ms/div to 0.05µs/div in 19 steps (1-2-5 sequence). X10 mag extends maximum sweep rate to 5ns/div. Horizontal Display Modes: A, A Intensified by B, B delayed by A, and mixed. CALIBRATED SWEEP DELAY Calibrated Delay Time: Continuous from 0.1µs to at least 5s after the start of the delaying A sweep. Differential Time Measurement Accuracy: for measurements $900 of two or more major dial divisions: +15°C to +35°C 1% + 0.1% of full scale; 0°C to +55°C additional 1% allowed. TRIGGERING A & B A Trigger Modes: Normal Sweep is triggered by an internal vertical amplifier signal, external signal, or internal power line signal. A bright baseline is provided only in presence of trigger signal. Automatic: a bright baseline is displayed in the absence of input signals. Triggering is the same as normal-mode above 40Hz. Single (main time base only). The sweep occurs once with the same triggering as normal. The capability to re-arm the sweep and illuminate the reset lamp is provided. The sweep activates when the next trigger is applied for rearming. A Trigger Holdoff: Increases A sweep holdoff time to at least 10X the TIME/DIV settings, except at 0.2s and 0.5s. Trigger View: View external and internal trigger signals; Ext X1, 100mV/div, Ext -: 10, 1V/div. Level and Slope: Internal, permits triggering at any point on the positive or negative slopes of the displayed waveform. External, permits continuously variable triggering on any level between +1.0V and -1.0V on either slope of the trigger signal. A Sources: Ch 1, Ch 2, NORM (all display modes triggered by the combined waveforms from Ch 1 and 2), LINE, EXT, EXT :-10. B Sources: B starts after delay time; Ch 1, Ch 2, NORM, EXT, EXT :-10. Optional cover for CRT screen – $35 through the vertical system. Continuously variable between steps and to at least 12.5V/div. X Axis Bandwidth: DC to at least 4MHz; Y Axis Bandwidth: DC to 100MHz; X-Y Phase: Less than 3° from DC to 50kHz. DISPLAY CRT: 5-inch, rectangular tube; 8 x 10cm display; P31 phosX-Y OPERATION phor. Graticule: Internal, non-parallax; illuminated. 8 x 10cm Sensitivity: 5mV/div to 5V/div in 10 steps (1-2-5 sequence) markings with horizontal and vertical centerlines further marked in 0.2cm increments. 10% and 90% for rise time measurements. Australia’s Largest Remarketer of markings Graticule Illumination: variable. Beam Test & Measurement Equipment Finder: Limits the display to within the graticule area and provides a visible 3167. Tel: (03) 9562 9500; Fax: (03) 9562 9590 display when pushed. MACSERVICE PTY LTD 20 Fulton Street, Oakleigh Sth, Vic., **Illustrations are representative only. Products listed are refurbished unless otherwise stated. November 1995  71 Fig.3: this diagram shows the front panel of the “mouse” remote control unit used with the Nokia 7163 colour TV set. The mouse function was not immediately obvious and the use of symbols and colours for some of the buttons didn’t offer much help when it came to using the device. horizontal flywheel sync system, particularly involving the flywheel time constant. So one might be tempted to pull the chassis out, find the appropriate section, and start trou­bleshooting – all this without the benefit of a circuit, at least initially. But, as I hinted earlier, European 72  Silicon Chip sets are different. Apparently, they find it necessary to provide a choice of fly­wheel time constants: long for off-air operation (particularly in fringe area situations) and short for VCR operation. I have no idea why this is so, particularly as American and Asian designs seem able to achieve a compromise setting which is quite satis­factory for both conditions. But that’s the way it is. And it meant that this set almost certainly would have this facility. And there was, therefore, little point in assuming a fault and pulling the set apart, if it was just a matter of resetting this adjustment. But, once again, I was at the mercy of the control unit, because any such adjust­ment would have to be made through it. As readers can imagine, with nothing more than an array of buttons on a control unit, and no other data, it was a formidable situation. And, to make matters worse, not all the buttons are clearly identified. While most are marked with words or numbers, the top four carry symbols and the four beneath them have both symbols and colours (the colour sequence, from left to right, is red, green, yellow and blue). Three other buttons, two below the numerical buttons and the other in the bottom righthand corner, also carry symbols only. Talk about starting from behind scratch! I switched the set on and it came up on one of the channels to which it had already been preset. I took a punt and pressed the menu button. This brought up a selection of menus and, after a lot of trial and error (read muckin’ about), I realised that all the menus –and there is a swag of them – can be presented in no less than nine languages. Unfortunately, Greek is not among them but, fortunately, the system had already been programmed for English. Pressing the video button brought up a menu offering colour (saturation), brightness, contrast and sharpness functions. Similarly, the audio button produced a menu offering stereo, hypersonic on, bass, treble, balance and volume – each with its own bargraph display for reference. The menus are presented as white characters on a black background, similar to some computer presentations. The exception here is the item that’s currently selected, which will have the reverse presentation; ie, black charac- ters on a white background (typically referred to as the “cursor”). All that was fine as far as it went. But how did one move the cursor to change the selection and, having changed it, acti­vate it? I found the answer quite by accident. I noticed that moving the control unit sometimes produced a sound from inside it and, at the same time, I realised that the cursor on the menu had changed. So this was their version of a mouse; a loaded contact ball inside the control which moved when the control was pointed up or down, or banked to the right or left. And, logically, the cursor moved up when the front of the control was lifted and down when it was depressed. For example, when in the audio menu, one could select, say, volume and then vary the volume up or down by rotating or banking the control to the left or right. Or one could select, say, brightness in the video menu and vary it in a similar manner. I was starting to get the hang of the thing now. But it was only the beginning; it was to take a lot more “muckin’ about” before the job was done. And it would be virtually impossible to set out all the things that can be done with this system or, indeed, how I worked out how to do them. We’d be here forever. In any case, I doubt whether the reader could follow it all, without the benefit of a hands-on approach. But I did make some notes as I worked out what I needed to do, just in case I had to do it again. These will give the reader some idea of what is involved. First, the tuning. Press the MENU button, then the blue button, to bring up MENU 1. Move the cursor to TV-PROGR and call up MENU 2 by rotating the mouse control. This gives a choice of tuning approaches: (1). The channel number mode. A number of frequencies are pre-programmed into the set – useful only if a list of channel frequencies is available. Enter a channel number – assuming that one is available to suit an Australian transmission. No channel list available. Resorted to search mode. (2). The search mode. Press the green button to change from channel mode to frequency mode. Press the MENU button and rotate the mouse to search for stations. When a station is found, revert to the channel mode to What about the user? And one has to admit that it is all extremely clever and ingenious. But how does it sit with the average user? Is he or she really expected to program such a complicated device? Among other things, they would have to select the appropriate TV system, find and store all the TV channels, consult and use the video adjustments and options, and carry out the sound adjustment options. In most cases, of course, a dealer would have already made the adjustments and the set would be ready to go on installation. The catch comes if the system has to be reprogrammed for any reason (eg, if the user moves to a different location). The reality is that they usually have to call in the likes of yours truly to do the job for them. And that costs money. Finally, there is the vulnerability of these systems by reason of all adjustments being accessible via the remote control. A careless user, or an inquisitive Little Willie, can wreck a long and complex programming sequence in a few seconds. Again, that costs money. So what’s the answer? I don’t know – I can only see the problem. And it’s a SC very real one. SILICON CHIP SOFTWARE Now available: the complete index to all SILICON CHIP articles since the first issue in November 1987. The Floppy Index comes with a handy file viewer that lets you look at the index line by line or page by page for quick browsing, or you can use the search function. All commands are listed on the screen, so you’ll always know what to do next. Notes & Errata also now available: this file lets you quickly check out the Notes & Errata (if any) for all articles published in SILICON CHIP. Not an index but a complete copy of all Notes & Errata text (diagrams not included). The file viewer is included in the price, so that you can quickly locate the item of interest. The Floppy Index and Notes & Errata files are supplied in ASCII format on a 3.5-inch or 5.25-inch floppy disc to suit PC-compatible computers. Note: the File Viewer requires MSDOS 3.3 or above. ORDER FORM PRICE ❏ Floppy Index (incl. file viewer): $A7 ❏ Notes & Errata (incl. file viewer): $A7 ❏ Alphanumeric LCD Demo Board Software (May 1993): $A7 ❏ Stepper Motor Controller Software (January 1994): $A7 ❏ Gamesbvm.bas /obj /exe (Nicad Battery Monitor, June 1994): $A7 ❏ Diskinfo.exe (Identifies IDE Hard Disc Parameters, August 1995): $A7 ❏ Computer Controlled Power Supply Software (Jan/Feb. 1997): $A7 ❏ Spacewri.exe & Spacewri.bas (for Spacewriter, May 1997): $A7 ❏ I/O Card (July 1997) + Stepper Motor Software (1997 series): $A7 POSTAGE & PACKING: Aust. & NZ add $A3 per order; elsewhere $A5 Disc size required:    ❏ 3.5-inch disc   ❏ 5.25-inch disc TOTAL $A Enclosed is my cheque/money order for $­A__________ or please debit my ❏ Bankcard   ❏ Visa Card   ❏ MasterCard Card No. Signature­­­­­­­­­­­­_______________________________ Card expiry date______/______ Name ___________________________________________________________ PLEASE PRINT Street ___________________________________________________________ Suburb/town ________________________________ Postcode______________ Send your order to: SILICON CHIP, PO Box 139, Collaroy, NSW 2097; or fax your order to (02) 9979 6503; or ring (02) 9979 5644 and quote your credit card number (Bankcard, Visa Card or MasterCard). ✂ allocate a number for it. It can also be given a name, if desired; eg, “Channel 7”, or “SBS”, etc. Save by pressing the red button. So, by this process, all the local channels were eventually located, stored, numbered and named. Then it was to the flag- waving problem. This was fixed as follows: Press MENU button. Brings up INDEX menu. Press blue button. Brings up sub-menu listing SAT-PROGR, TV-PROGR, EXT-PROGR. Select EXT-PROGR. Brings up sub-program listing, among other functions, SYNCHR-VCR. Select the latter. Rotate control to switch to long time constant. And that was it; problem solved. It sounds easy when you say it quickly but it wasn’t easy, of course. It took many hours – and much colourful language – before the two above routines were worked out and completed. But by the time I had done it all, I realised that I was beginning to enjoy the challenge; that, in fact, I was being sucked in by the technology and the ingenuity behind it – much as I suspect the engineers who designed it were sucked in. November 1995  73