Fullscreen

A nostalgic look Colour TV in Aus Although a sizeable proportion of readers will have never known anything else, it’s incredible to think that March 1st, 2005 marks the 30th anniversary of the commencement of full-time colour television broadcasting in Australia. What is even more remarkable is the number of colour sets that were there for particular milestone and are still working, in many cases still with superb picture quality! I   personally have a 5-set “working museum” of 30-year old sets “billeted” at various relatives’ houses, still in everyday use. And I’d have more if I had the room… In the early 70s, we were piously informed that the maximum working life of a colour picture tube was “about seven years”! In many ways the advent of Colour TV in Australia is a bit like the Second World War: for people like myself, born after 1945, WWII is an event that has always “been there” – but mainly in the sense of the lingering effect it has had on people who lived through that time. Just as there are still plenty of people alive who can remember a dramatically different time before there had ever been a Second World War, there 32  Silicon Chip are plenty of older electronics technicians who remember what it was like when there were no colour TV sets! As with WWII, a staggering number of things changed beyond recognition in just a few short years and there were many casualties left by the wayside. I’ve watched the average 67cm colour TV that needed two people to lift it, had just a mechanical channel selector (usually VHF-only) and no remote controls, evolve into today’s comparatively feather-light equivalent with a window-flat, absolutely rectangular screen, full remote control and multiple video inputs. The average 1974 product cost by Keith Walters around ten weeks of the average worker’s net wages; you can typically pick up today’s version for 3 days net wages . . . or even less if you opt for an old-fashioned curved screen! And people may baulk at the price of today’s Plasma sets but in real terms they work out considerably cheaper than the first colour sets. Right place, right time I started my electronics career in early 1972 at the Brisbane branch of a well-known nation-wide TV service company, so I was right there at the transition to colour. In those days, many electronics enthusiasts my age were keen to make some kind of career in electronics, often for no other reason than working for some sort of “official” organisation siliconchip.com.au k at the start of stralia was about the only practical means of getting any regular access to the electronics “real world”. You have to understand that this was long before the advent of nationwide Dick Smith and Jaycar type specialist electronics supermarkets. Things may have been easier in Sydney and Melbourne but for the rest of Australia, obtaining parts for magazine projects was an expensive and often frustrating business. Electronic component sales were often seen as a relatively unimportant sideline for electrical wholesalers. Buying even fairly run-of-the-mill (by today’s standards) semiconductors often entailed long trips out to obscure industrial estates on the other side of town! I was certainly in the right place at the right time, as the early seventies were an exciting time for electronics in this country and elsewhere. Up until then, apart from the proliferation of “transistor” radios, solidstate circuitry had made relatively little headway in consumer applications. Solid-state technology had certainly been advancing at an incredible pace but most of the activity was in more “serious” fields like the military and computers. siliconchip.com.au Computer manufacturers had started abandoning valves at least 15 years before – out of sheer necessity – but even here the seeds of the future were being sown; in March 1972 the robot space probe Pioneer 10 set out on its history-making mission to Jupiter and beyond. Its on-board computer was based on Intel’s (and the world’s) very first microprocessor, the 4-bit 700kHz 4004, the direct ancestor of today’s multi-GHz Pentium CPUs! The mission was supposed to run for just two years but as it turned out, most of it was still working (computer and vidicon TV camera included) when the probe finally moved out of radio range in 2003! Back on Earth, ICs were becoming steadily cheaper and more plentiful. In Australia in particular, changes in tariff policies were making imported electronic parts cheaper and more accessible, as decades of “stone wall” tariff protection were steadily wound back. Electronics retailing changes A now long-defunct company called Kitsets Australia (remember Kit: “Keep your irons hot, boys . . .”) had just opened the first tiny “Dick-Smith- style” retail outlet in Brisbane. (Dick Smith was operating his first store in Sydney at the time but he didn’t open in Brisbane until quite a bit later). It was quite a big deal to be able to actually see what a magazine project looked like and speak to people who actually knew what we were talking about! And for the first time, parts became a lot easier to get. They even offered mail order for those in the sticks. Servicing changes Those were interesting days in the servicing field too; transistors were finally beginning to catch on with TV manufacturers. Prior to that, apart from portable sets, they had obviously seen little reason to change from the valves that had served them so well for the previous 15 years. “Electronics service” then was pretty much “TV service”. It’s hard to imagine it now but in those days there were no DVD players, no personal computers, no microwave ovens and, apart from portable record players and AM radios, not all that much in the way of sound equipment. If a household boasted any sort of “music system” at all, it was usually March 2005  33 two types of picture tube: the older, wide-necked 90° deflection type with the bakelite base, or the more modern, all-glass, 110° narrow-necked type. If a set had to go to the workshop, it was more usual to simply “pull” the chassis and leave the tube and cabinet behind. Most workbenches were equipped with one of each type of tube on a special stand, a loudspeaker and an audio output transformer combination terminated with crocodile clips and an orientable mirror. An oscilloscope was considered a luxury and it was more often a case of “one per workshop” than “one per tech”! The winds of change My late father’s pride and joy: his 34cm AWA colour portable – probably the reason I started writing this history in the first place! When I bought it for him in 1975 he didn’t expect to be with us much longer and so he kept remarking that the little set would “see him out!” However he got over that illness but true to his word, when he finally passed on 28 years later in September 2003, aged 98, the set was still going, with the picture tube as good as the day we bought it! a radiogram (an AM-only radio, perhaps with shortwave, plus a turntable – itself often capable of playing only 78 RPM records), or if they were really well-off, a “Three-in-One” TV and radiogram combination. FM radio and CDs were still more than a decade in the future and even audio-cassette decks weren’t all that common (reel-to-reel tape recorders were becoming popular). The nearest thing to a mobile phone was a (very expensive) dash-mounted two-way radio! Philips had demonstrated “proof of principle” versions of both home VCRs and videodiscs even back then, but commercial versions were still some years off. The 1960s serviceman A typical field serviceman’s tool kit consisted of a soldering iron (as often as not a “Scope” quick-heating type which could do a great job on guttering but not quite so good on delicate components!), some basic hand tools (side cutters, long-nose pliers and a few screwdrivers), a “20K per volt” analog multimeter, a small selection of plastic ferrite slug twiddling tools and most important, a “quarter inch” nut driver! 34  Silicon Chip A large percentage of the woodencabinet TV sets had their backs fastened on with special screws that could only be removed with this particular tool, presumably to deter idle twiddling by the uninitiated handyman! On my first day on the job I was assigned a vacant bench and amazingly, its previous occupant had cleared its drawer of every item, except for one of these esoteric and hard-to-get tools… I still have it too! The rest of a travelling serviceman’s accoutrement usually consisted of a briefcase full of the more common valves, some 100mF high voltage electrolytic capacitors, a selection of 600V polyester capacitors and usually, the full “E12” range of 1W resistors. There was also usually a small box of odds and ends, germanium and silicon diodes, a few common knobs and so on. The more progressive tech might have carried a CRT “Zapper” (rejuvenator), often home-made and of dubious efficacy! There was a reasonable degree of standardisation in Australian TV set manufacturing, which meant that there weren’t too many different valve types used. There were really only So until about 1970, setting up a TV workshop wasn’t a particularly costly nor involved undertaking but the winds of change were starting to whistle around the door frames. By the end of the decade they would reach hurricane force but we weren’t to know that. It all started in a modest enough way. With the prospect of all-solidstate colour TV receivers on the horizon, some of the manufacturers obviously thought they should get in some “practice” by experimenting with all-transistor large-screen monochrome sets. Actually, since the late ’60s, most manufacturers had been flirting with “hybrid” designs of one sort or another, made from a mixture of valves, transistors and occasionally, even (the then dreaded) ICs! The “grunt” sections (horizontal/ vertical deflection and audio output) were handled by traditional valve circuitry, with transistors (and occasionally, ICs) in the low-power signal processing. It’s interesting to note, though, even when colour TV set sales were well underway, some local manufacturers were still manufacturing and selling all-valve large-screen monochrome sets! From this distance, it’s really hard to see what the point of a lot of this “hybrid” nonsense was. The simple replacing of a valve with a transistor in the low-power signal processing sections had no real cost advantage. And since the bulk of the set’s power was still consumed by the valve audio, vertical and horizontal output stages, there was little or no cost saving in siliconchip.com.au manufacture or electricity consumption either. Apart from this, most valves used were multi-function, most usually a triode and a pentode in the same envelope, so you needed at least two transistors to replace most valves. Maybe the engineers were merely trying to get some solid-state design experience under their belts – but if they were, they were fiddling with the least problematic parts of TV design! This was an even more eccentric approach when you consider the case of European sets which usually didn’t have power transformers. (AWA and Thorn made localised versions of the British Thorn “R” chassis but fitted them with power transformers). In valved signal-processing stages the bulk of the power consumed is simply used by the valves’ heaters. However, since all the heaters in a “transformerless” set were normally connected in series and fed from the 240V mains through a dropping resistor, to maintain the correct heater current in a hybrid set extra resistance had to be added, to substitute for the replaced valves. So practically the same amount of power is used, regardless! (Of course it’s an entirely different story with a colour set, because there’s a lot more signal processing involved). Just about all the major manufacturers produced monochrome portable sets and you’d think, well here at least is a reasonable justification for going for all-solid-state designs. But ironically, two of the most popular “12 inch” portable designs were those made by AWA and General Electric and they were all-valve! At the same time, AWA was making “Hybrid” large-screen sets and all-valve 12 inch portables! (It was also something of an industry joke toward the mid-70s that only remaining manufacturer of valve portables was National/Panasonic, whose slogan went: “Just slightly ahead of our time!”). Of course, if you wanted AC/DC operation, transistors were the only way to go, and although most manufacturers also produced all-solid-state designs, by far the most popular were the HMV models, starting with the infamous “Z1”. Popular? Well, I don’t know if “popular” is siliconchip.com.au Here’s the rear view of the AWA set shown on the opposite page. It only broke down once in 28 years (actually after 22 years) when the damper diode suddenly went short-circuit. And at the time I happened to be staying there, with my tool kit, and with a suitable replacement on hand… Probably just as well, when you look at the way everything was shoe-horned in! the right word but we certainly saw a lot of them. I don’t know what sort of people they had in their design departments either but it appeared that none of them understood anything about RMS dissipation in rectifier circuits, because they all used the same cheap 1A power diodes in a bridge passing about 2.2A! This gave the diodes a life expectancy that could best be described as “toasty, brutish and short”… They also nearly all used the same 11V regulator circuit based on a PNP germanium power transistor. This frequently went short-circuit, often taking out the high voltage germanium horizontal output transistor and/or the selenium EHT rectifier. Then there were the dreaded “green lollies”, a popular type of high-value polyester horizontal yoke coupling capacitor which was forever going short-circuit. All in all, they were certainly a reliable meal ticket for the few technicians willing to put aside their technical insecurities and “have a go”. Kriesler were probably the most serious about large-screen all-transistor sets, with their (in)famous 49-7 chassis. Overall, the 49-7 wasn’t a bad design and I believe there are still a few of them out there! It featured a regulated 35V power supply based on a BDY20 (2N3055) power transistor, a horizontal output stage that used one of the new BU105 1500V silicon power transistors running from a boosted HT line of about 120V, another BDY20 for the vertical output, and a BF177 high-voltage video amplifier stage. Valve jockeys Why “infamous”? Well, all this hightech stuff was good news for brighteyed 19-year-olds like me, raised on a diet of EA/ETI magazine projects, but not so hot for the generation of “valve jockeys” that preceded us. And there were a lot of these somewhat pathetic individuals (often exmilitary with no real theoretical background), who one way or another, had learned to recognise the common faults that plagued old valve TV sets (usually the valves themselves) and could eke out a living armed with a screwdriver and case of spare valves! Most of them eventually learned to recognise other common faults like dried-up electrolytics and leaky paper capacitors. I suppose as long as there was a competent workshop to back them up, they March 2005  35 could usually be relied upon to put in a reasonable day’s field work. The new solid-state techniques changed all that, with the triplewhammy of all-soldered-in, all-solidstate components, mounted on printed circuit boards. Imagine how one of those guys would have felt, the first time he took the back off a sparkling new Kriesler all-solid-state chassis! A new breed of technician was required, able to wield multimeter, oscilloscope and solder sucker with equal facility – and there weren’t too many of those around! (Not for a while, anyway). Well, I guess we should make that a “quadruple-whammy”, what with colour looming on the horizon! When I started, colour TV was still a few years away and so all the sets I encountered were monochrome, many of them dating back to 1959 when TV first started in Brisbane. (A few were even older, having “migrated” up from Sydney!) Incredibly, until at least the early 1990s they still had some of these “originals” under service contract! It seems as long as the customers kept paying the money (and they could get the parts; mostly just valves and other common “generic” items), it wasn’t considered any big deal to make a service call every two years or so! And it’s not all that surprising, really; some of those old sets were incredibly well made; most of them got the chop simply because they were replaced with colour sets! About 15 years ago I helped in the restoration of an original Australianmade 1956 Admiral 21-inch TV. By an extraordinary stroke of luck we managed to locate a working reconditioned picture tube and some of the “oddball” valves that Admiral used. It still works, the printed circuit boards being in perfect condition after nearly 50 years! So in 1972 the vast majority of day-to-day service work consisted of mostly elderly all-valve jobs, with a sprinkling of the “hybrid” types and the occasional all-transistor model. In the case of the older all-valve sets, as with vintage radios, most of the problems were caused by the old style paper capacitors and other passive components. If you have any notions about the new hybrid designs being more reliable, I can assure you, in those there 36  Silicon Chip One of the “newer” Rank Arena sets – basically, a re-badged NEC. Legend has it that a consortium of local manufacturers was offered the choice of the Britishdesigned “true” Rank chassis or a badge-engineered NEC chassis. They took one look at the British effort and took the NEC option! were far more transistor failures than valves. At least with a valve it’s just a matter of plugging in a new one! (Anybody remember those awful black “Anodeon” transistors?) Chroma locked colour TVs Colour TV sets actually began to appear in Australia on a peculiar sort of “grey market” basis in the early 1970s, taking advantage of a technological quirk peculiar to the PAL system. Although there were no official colour broadcasts (and no colour production or playback equipment in the studios), many TV programs sourced from the UK and Europe were supplied on colour videotape. And although they were never designed for it, most of the more recent monochrome studio video recorders could reproduce the colour subcarrier to a certain extent. The Government wasn’t happy about some sections of the community jumping the colour gun, so to speak. So the TV stations were required by law to suppress the colour burst so that any PAL colour sets would only display the pictures in monochrome. But “those in the know” discovered that by the use of an add-on gadget called a “chroma lock” this lack of burst could be overcome (with certain limitations) and quite often, excellent colour fidelity was obtained. Sometimes the chroma lock locked the colours out-of-phase so that all colours were negative of what was expected (the “green face” syndrome often experienced on NTSC pictures those days). A tap of the chroma lock button usually fixed that little problem. AWA imported and sold a few hybrid German Telefunken sets with this facility built in and most technicians with access to colour sets experimented with this technique, often sitting up until the wee hours to watch English Soccer in colour! My first colour TV The first colour TV I ever got to actually lay my hands on was a 26-inch all solid-state “Decca” (actually made by HMV), specially imported from the UK for training purposes in 1973. It was a pretty conservative design, with an SCR-regulated 125V HT line, a 66cm 90° delta-gun picture tube, and mostly discrete components in the signal processing sections. It was a fascinating piece of kit to those of us who’d never set eyes on a colour TV set before but as it turned out, it didn’t have all that much in common with the designs that were siliconchip.com.au eventually manufactured and/or imported here. Fitted with a chroma lock board borrowed from HMV, it did the rounds of a series of beer and prawn evenings held in various technicians’ homes when certain programs known to be in colour were on. The management obviously hoped that curiosity would overcome their abject fear of the Technicolor monster! There usually wasn’t much on during the day. In fact, the first time we saw anything really significant was the 1973 Melbourne Cup. I remember I had the devil of a time dragging the office workers away from the old Pye B&W TV they were crowded around to show them this new marvel. This from a company whose offices were plastered with posters proclaiming their “Engineered for Colour” range of TV antennas! Then we realised that the upcoming live-by-satellite telecast of the wedding of Princess Anne in November 1973 was not only sure to be in colour but also on in the early evening (as it would be morning in London then). Unfortunately a lot of other people realised this too and a few days before the blessed event, HMV wanted their chroma-lock board back! Luckily, I’d already been working on one of my own and I managed to get it ready in time for the big event. But as Murphy would have it, we couldn’t find a single piece of colour material to test it on. “Oh well”, we thought, “we’ll just stay back and see what happens anyway” but around 7pm other people started to arrive. Lots of people – managers and their wives, people carrying cartons of beer and real food! Soon they were everywhere, dragging chairs out of the offices, sitting on boxes, whatever they could find, and eventually the whole loading dock was packed with slavering Royal watchers. Did it work? Yes, thank God, it was actually the best colour broadcast we’d ever seen! State stupidity Of course, no amount of beer and prawns was ever going to substitute for proper technical training but at least it got some of the older guys to actually consider the possibility that they might possibly be of some use when colour came for real! siliconchip.com.au In Queensland at any rate, our quadruple-whammy was really a quintuple-whammy: the state-run technical colleges announced that their colour TV training courses would only be available to people who had undergone official apprenticeships. This probably excluded about twothirds of the Brisbane technical staff, and for that and other reasons, our parent company decided to set up its own in-house training program. A jaundiced view In mid-1972 I was fortunate enough to be struck down with a severe case of hepatitis, requiring a six-week stay in hospital. Why “fortunate”? Well, it worked out rather well for me as I had just bought G.N. Patchett’s excellent textbook: “Colour Television With Particular Reference to the PAL System”. With nothing else to do I applied myself to the subject diligently and came out of hospital something of an expert in the field! We also had the usual assortment of people with “overseas” experience who naturally made out they knew all there was to know about colour TV but when our Decca training set was finally unboxed with an enormous purity error, not one of them seemed to have any idea what to do about this common problem! Yet the procedure given in Patchett’s book couldn’t have been much simpler: “Display a red screen. Loosen the two wing nuts attached to the deflection yoke and slide it backward; this should produce a circular red patch at the centre of the screen. Manipulating the purity magnets as you would picture centring magnets, centre the red spot on the screen, push the yoke back forward until the red fills the screen, and re-tighten the nuts.” Which I did . . . and it worked! Training the untrainable? At this point the management realised that there was a long way to go – they hadn’t even gotten their technicians up to speed on solid-state technology and there was colour TV staring them in the face! It was a very long, arduous and thankless process I can tell you. The only training material available was mostly from the US and the UK and although it covered the basic theory well enough, the descriptions of “typi- cal” colour set designs were years out of date. So we basically had to write our own, using whatever technical information we could scrounge from the local manufacturers and technical colleges. There was also a severe discipline problem, typical of any situation where you’re trying to teach a group of middle-aged people anything! Every time we got a group of technicians together for whatever reason, the discussion would always degenerate into a discourse about how all their problems would be solved if the company simply stopped renewing service contracts on sets more than say, 10 years old. In the end the managers got jack of this and in the first hands-on example I’d ever seen of the awesome power of computer technology, they ordered a special printout of the last three years’ “activity” of a couple of thousand of their service contracts. The printout showed the year of manufacture, the make, and the number of service calls for each of the three years. I can still remember the General Manager laying down the law, too: “Look: There! ‘Year of Manufacture: 1959; Service Calls: 1971 – none!; 1972 – none!; 1973 – none!’ Look at this one: ‘Year of manufacture: 1961’: no calls! Here’s one with just one call! I mean, all these people are paying us $39 year, mostly for doing nothing. Even if we do make a call, how much does that cost us? Half the time you don’t even use any parts, and even if you do, most of them cost next-to nothing!” I don’t recall his closing comments but they were the 1972 equivalent of: “There’s still money in it, guys; deal with it!” If it had been me, I might have also added something to the effect that getting rid of a lot of the old sets would allow them to get rid of a lot of the “dead wood” in the company, whether this was actually true or not… SC NEXT MONTH: In the second part of this feature, we’ll have a closer look at the good, the bad and the downright ugly: the TV sets that ushered in the colour TV era in Australia. March 2005  37