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Last updated
10 Jan 1998


sinclair@nvg.ntnu.no

The TV1A/B/C/D and Mon1A

The Microvision TV1A (right) was launched in January 1977, but it was the result of a long, slow and expensive development process which went back as far as 1963. Sinclair had long wanted to produce a miniature TV and, in 1966, succeeded; the prototype Microvision was launched with much publicity at the 1966 Radio and Television Show in London. However, the difficulties of manufacturing it forced Sinclair to put it on the back burner for a decade until technology had caught up with his vision.

The moment came in 1976, when the new Microvision - now formally the TV1A - was launched in the United States. It was modestly popular, with about 35,000 sold, but could not be produced in large enough numbers to make it profitable. In a classic Catch-22, by the time Sinclair was able to ramp up production to the break-even point of 4,000 a month, demand had slumped and unsold stock built up rapidly. The backlog of 12,000 TV1As was eventually resolved by selling them off cheaply at 60 each. Unfortunately, they cost 100 each to make, so resulting in a 480,000 loss for Sinclair at a time when the company could least afford it.

Sinclair himself was certain that the "new and improved" TV1B - a more efficiently designed model, launched in the autumn of 1978 - would take off, causing demand to spiral and saving the company. The TV1C and TV1D were, respectively, US and European variants of the TV1B, adapted to work with the local television systems. A mini-monitor, the Mon1A (right), was also produced, employing the TV1A hardware.

In the event, the gamble failed. The TV1B/C/D was the last product from the Sinclair Radionics stable. In July 1979, the National Enterprise Board - Sinclair's government backers - finally got fed up and pulled the plug on the company. Sinclair received a 10,000 "golden handshake" and set up Science of Cambridge instead. The rights to the TV1B were sold to Binatone, but - like Amstrad and the Microdrive a decade later - they dropped the product.

But Sinclair did not give up his dream of producing pocket TVs - in 1984 he tried again with the TV80, which once again was modestly successful but did not recoup the cost of development.


The picture in your briefcase; when time stood still
(From The Sinclair Story, by Rodney Dale)

From time to time in this narrative, like a faun a-peeping through the green, we have espied Sinclair's elusive shade, the miniature television. It is no surprise that, with his passion for the miniature, Sinclair should have turned his attention to television; what is surprising is that success eluded him for so long.

When he was working on Instrument Practice, finding out all he could about semiconductor devices, one of his topics of conversation was the possibility of building a miniature television set. One of my first jobs when I joined Cambridge Consultants full time at the end of 1963 was to search, on Clive's behalf, for a supplier of miniature television tubes with a screen 4cm x 3cm. I did obtain some sample glass 'envelopes' from Tony Krause of Twentieth Century Electronics, but as far as I know they were never equipped with any innards.

Whatever difficulties there were in producing an elegant circuit design were overshadowed by the difficulties of finding a miniature tube, and even miniature tubes still needed enormous power to run them compared with that needed by the rest of the set. Twenty years ago there was no low-power CMOS circuitry, and for continuous viewing batteries would have been needed which were larger than the machine itself. Typically, Sinclair's inventiveness lay far ahead of what was practicable. Not that this stopped him from pursuing the project; one of the first TVs they made used a sawn off bit of a Sony 5" tube with a home-made bit bolted on to it to produce a 2" diagonal picture. Sinclair went off to see what was happening in the Far East and returned to his designers with all sorts of interesting components and a number of the crucial cathode ray tubes from Hitachi. Jim Westwood, who had been concerned with the development right from the start, set to work, and by 1966 the team was ready to show a prototype Microvision, as the product was inevitably called. Sinclair Radionics booked a stand at the Radio and Television Show at Olympia and as the great day loomed nearer the team worked more and more frantically, later and later into the night, to have a couple of sets ready.

Less than a week before the show was due to open - on the following Monday - some vital components still hadn't arrived. There's nothing you can do about exhibitions; like any other entertainment the show must go on, and many an exhibitor knows only too well the frantic preparation culminating in round-the clock working and the final coat of paint even as the Minister of Technology is saying what a jolly good effort it all is, and cutting the ribbon.

This exhibition was no different; the vital components finally turned up on the Friday, and Jim Westwood went to work immediately. He worked throughout the weekend, hardly stopping to eat or sleep. But it was the first time that the various parts of the circuit had been put together and naturally there were some unpredictable incompatibilities to be ironed out before the sets would work. Sunday afternoon: still no pictures.

It was decided that Richard Torrens should set off for London on his own with the other products Sinclair Radionics was going to exhibit. Jim Westwood carried on working. At 3 o'clock on Monday morning he was ready to leave the lab; he called the taxi that was on standby and set off for Olympia. He had one Microvision working and another needing only slight adjustment.

The prototype Microvision was a 2" 405-line receiver which would handle all 13 channels in bands I to III. The speaker was a 2" piezoelectric transducer with an overall depth of less than 1/4". The set was powered by six pen light cells, and its total power consumption was less than 450mW, including less than 100mW for the tube heater. Its weight, including the battery, was 10V2 oz. The cathode-ray tube was designed by Twentieth Century Electronics; using magnetic deflection, it was just over three inches long, and there were some problems both in handling it and in assembling the set so that the spot would remain adequately focused. Rather than using an integrated circuit, which would have been ruled out by the additional heavy investment needed - for had not Sinclair already invested heavily in the tube? - the Microvision contained 30 transistors and other discrete devices assembled together in a three-dimensional package. The packing density was incredible: components stood on end where there happened to be convenient holes, otherwise they lay down. Its design made the Microvision very difficult to test, service and repair.

And it had an interesting side-effect. Chris Curry saw an example of this marvel of compactness sitting on the bench, and, with natural curiosity, picked it up. OUCH! The set was switched off, but its EHT capacitors were charged up to 2,000 volts. Fearful of the consequences of dropping it, he tossed it into the air and caught it. OUCH! The process continued until all the capacitors were empty.

Despite its obvious shortcomings, the Microvision was the star of the 1966 Radio Show. Three girls, dressed all in silver - Clive's sister Fiona, his sister-in-law Carol, and Sally Willey - ensured that no one missed the Microvision, and would have distracted the attention of the visitors if the sets had packed up. They didn't pack up. A few orders were placed by the intrepid in the expectation that the set would be on the market the following year, priced at 57.45, But it was never really ready to be launched; the few orders were never fulfilled.

This was partly because of the difficulties in manufacturing the tube and partly because of a fundamental design change: silicon transistors had just become available and were obviously going to be cheaper and more stable than the germanium transistors used in the Microvision. It seemed eminently more sensible to carry out further development before going to the market-place again.

Throughout the early and middle seventies there were reports in the press that the design of the Sinclair television was nearly complete - and usually about a year from production. Rumours were rife; the TV became smaller and smaller, and one report even suggested that Sinclair was really working on an eye-level television that could be worn like a pair of spectacles!

The two overwhelming problems in developing a small television are the circuitry and the tube, which doesn't leave very much to achieve without effort. In 1973 Mike Pye left Texas Instruments - where he had been working on integrated circuits to join Sinclair Radionics. He was to be research and development controller for new projects; new projects included a 2-inch screen portable television. Technology transfer: Pye knew about the right kind of integrated circuits so it was now a matter of finding the right kind of tube. He rediscovered Tony Krause, who was by then Chief Engineer at Twentieth Century Electronics, and who had been developing a tube for a flat screen television.

Sinclair was impressed with Krause's work, and it wasn't long before he left Twentieth Century and joined Sinclair Radionics as a consultant. Tony Wood Rogers joined at about the same time, also to help develop the cathode-ray tube.

The first outcome of this collaboration was the 'coffin' tube, which was about 6 inches long and presented a picture about the same size as a 35mm slide. The glass envelope was formed from three pieces: the front cap, the top, and the bottom: in shape, it resembled a coffin.

It was a low-power electrostatic tube with the electrodes mounted on long wires held in place by a frame while the three glass mouldings were fused around them. Positioning the electrodes accurately needed the skill of the watchmaker. And when the tube had finally been assembled and pumped out, the components were mechanically very resonant; as you might imagine, if you tapped the tube the spot would swing all over the place.

Eventually Clive was forced to call it a day on the coffin tube. It was a fine design, but far too difficult to manufacture. In fact, apart from the prototypes, none was ever produced. However, as Sinclair has remarked: 'I have an appalling habit of believing I'm right, and once I decide where I'm going I'll get there, come what may, however much I'm drawn off course by circumstances.'

Where next to look for a tube? Sinclair found that ITT had been working on a TV project in the late 1960s, for which AEG Telefunken had been experimenting with low power consumption tubes. They had a number of interesting designs, and after some discussion agreed to help to develop a tube exclusively for Sinclair Radionics. Their investment in the development was eventually about 200,000, not to mention the 25,000 they paid Sinclair to help fund their part of the development. The outcome of this work was that the TVIA - the new Microvision - was launched in 1976, ten years after the original model had been shown at the 1966 Radio Show.

The TVIA was aimed at the international business market, mostly because of the price - 250 while the up-market version, complete with power supply in a lined case was 650 from Harrods and Fortnum & Mason. The set was 4" wide, 6" deep, and 1.5" high. It operated either from rechargeable batteries or from the mains. The black-and-white picture could be viewed comfortably from about a foot away. It functioned on VHF and UHF bands and was the first-ever multi-standard receiver, which meant that it could be used in nearly every foreign country as long as the country used one of the three major TV standards. It weighed some 26 ounces.

The key component was the 2-inch tube manufactured by AEG Telefunken. The body of the tube was pressed glass made of two halves split longitudinally. There was no internal graphite coating; instead a metal shield was used to collect the beam current the swinked electrons which in their prime had caused the screen to fluoresce.

The bulk of the electrical circuit was contained in five bipolar ICs, three of which were custom-designed for Sinclair Radionics. The TVlA was significant not only because of its size but also because Sinclair was no longer taking available component hardware and adapting it; he was now taking tricky design problems by the horns. The TV1A's integrated circuits, tuners and tube were nearly all designed from scratch. It augured well for British electronics.

By this time Sinclair Radionics had a large export market, primarily because of the calculators, so it was not long before the TV1A was being offered in Germany and the States. In fact Jim Westwood had taken an American version of the 1966 Microvision to the States in l968, but it hadn't worked very well and the Americans had not been particularly impressed. However, there was no reason why the Americans should have remembered that Microvision, and once the TVlA had been launched in the UK, it was decided to display it at an exhibition in Chicago in January 1977. This event is photographically lined on the tablets of Jim's mind because no one in the company had appropriate export experience at this stage, and it was not until 15 December that he was told what to go on show in the US the TV would have to undergo tests for approval by the Federal Communications Commission and the Department of Health, Education and Welfare in the US to ensure that no one would be X-rayed or suffer from electrical interference. Clearance normally took between three and six months! Luckily, the Electrical Research Association at Leatherhead agreed to test the Microvision just before Christmas, and Jim Westwood recalls stumbling around in heavy snow and failing light at an RAF test range; as [he day merged into night, the tests were carried out with the help of car headlights and torches. But it was all worth while; approval was granted just in time for the exhibition.

The TVlA went on sale in the United States for $400. Although orders began to come in, it was fairly obvious that to sell enough sets to cover development costs Sinclair would have to lower the price. As one magazine pointed out 'At nearly 10 an ounce it would be a third of the price in solid sterling silver'!

This time, the Americans were impressed. In GADGET, the newsletter for grown-up kids, 'A.G.' reported on the Microvision he had bought from Abercrombie & Fitch, New York City, for $400.

'I felt like a kid awaiting Christmas morning. Finally it came: the most exciting and ballyhooed new toy of 1977, the Sinclair pocket TV set. I rushed out to buy it the minute it became available in New York, even though $432 (including sales tax) is a hefty price for a black and white television,

'The set is as revolutionary as all the advanced blurb indicated. But before the praise, let's first get its defects out of the way. My original unit broke after three days, when the tuning control jammed. Thankfully, Abercrombie & Fitch has one of the best return policies in Manhattan so the store gave me a brand new set on the spot rather than giving me the discount store runaround by forcing me to wait for repairs.

'My replacement set is not without other flaws. For instance, in a car the picture is far from stable; it tends to roll around. (New York City's skyscrapers contribute to this, no doubt.) Also, the set has a 15-second warm-up period. Another irritation is that the tuning device is incredibly slow-moving. One final gripe: when the set is plugged in for recharging, there is no visible glow light to verify that recharging is taking place. But despite these nitpickings, any GADGET reader who doesn't buy a Sinclair Microvision simply cannot afford to.'

But A.G. - clearly an indefatigable gadgeteer - then sets out to extol the virtues of his set:

'Another great capability is that this is the only set that can receive throughout the world, wherever there is a television signal. According to the company, it is the only such multistandard set available today.

'The best thing about the Sinclair Microvision for GADGET readers is that, in spite of its smallness, it's conspicuous. Wherever you are - buying a beer, having a cup of coffee, or simply sitting on a park bench - people will come over and ask questions about the set. It's like being the first kid on the block with the Captain Midnight Decoding Ring - you're the center of attention. After all, isn't that why you're a Gadgeteer?

'On the more practical level, the Sinclair does plug you in to the world of not-to-be-missed TV shows. Sure, some of you GADGET readers have video equipment that can tape a show you would otherwise miss, but with the Microvision you can watch it as it's broadcast wherever you are. Ironically, I got my Sinclair one day after the New York City blackout in July. If I had had it earlier, I could have watched the goings on in the city while the electricity was out, since NBC and CBS continued broadcasting on emergency generators.'

And A.G.'s conclusion?

'Clive Sinclair, president of the company that makes the Microvision can be proud of his accomplishment. Although we cannot give this set unqualified praise, we still think it is an exciting contribution to our lifestyle, and we recommend it to GADGET readers. If you purchase your set from a top-notch store with a good record of replacing defective items, you will be thrilled to own this electronic miniature.

'Hopefully, within the next two or three years, Sinclair will bring us a pocket set that will enhance viewer pleasure even more by including a color picture tube.'

Unfortunately, the price was governed by the cost of the special circuitry that enabled the set to work on several different transmission standards and consume less power, so there was no way of lowering the price on that particular model. There were also the inevitable production difficulties, although the sets that were sold generally worked perfectly. Sinclair had already learned the importance of quality control; a sample from each batch of televisions underwent rigorous tests before the batch was released.

There was soon an adaptation of the TV1A on the market: the monitor Mon1A. The principal user was a company called Bywood who used it as a tiny monitor with a display of 10 lines with 15 characters. It had an extremely rugged case, as used in police walkie/talkies. Sales of the Mon1A were small but consistent, and continued for a number of years.

Sinclair was determined to make the TV1A as small as possible because: 'This is a pocket portable; ifyou can't get it in your pocket it's not a pocket portable'; once again, the components were tightly squeezed into the space available, and this made it difficult to manufacture. There was a very small clearance between the PCBs - which sometimes carried quite a high voltage (up to 2kV EHT) - and the case. It was therefore necessary to put an insulating layer inside the case, but when it came to assembling sets there were problems in getting the case sleeve over the innards and, if the insulation ruptured, short circuits were inevitable. It was really only a matter of a fraction of an inch, but by the time anyone realised the difficulties it was too late.

However, the company managed to bring the output of the TV1A to about 4000 a month by the Christmas of 1977. There was now a labour force of 150 in the factory at St Ives, half working on TV1A; 75% of the output was exported, chiefly to the United States.

Meanwhile, development was pressing on with the next model, the TV1B. John Lawton, who designed its sound system, remembers: 'It was hell in the production department, I kept my nose out of there, there was too much going on. They had a flow-soldering machine which cooked the boards being used for the TV1A. These were very thin SRBP boards and someone would turn the temperature up too high occasionally, which warped the oards and made inserting them into the case even more difficult.'

The TV1B was known as the 'plastic box TV'. It was designed for automatic production and very low production costs. In the TV1A all the components were inserted manually into the five PCBs, using overhead projectors. In the TV1B the main circuit fitted on to a single PCB which was double-sided and through-hole plated. This more expensive technology, which was new for Sinclair, allowed a much higher component density and automatic production. The other PCB was a new high-tech UHF stripline tuner. The prototypes were built in Radio Spares plastic boxes.

The first version was for the UK only because a VHF tuner, which was not available at the time, was not needed. It used the same video ICs as the TV1A but the sound system was reduced from two ICs to one. The speaker was made in Taiwan and was much smaller, and there was a new AEG high brightness tube. It had an automatic brightness control but produced an inferior picture because there was no black level clamping. The power consumption had been reduced so that the set would work on four calculator batteries (HP11s) which could be replaced or recharged. It would run for about eight hours per set of batteries, which meant that it cost 12p an hour to run.

The TV1A had had a metal sleeve case with plastic ends and this had caused some of the shorting problems; the TV1B slipped into a plastic box which, once tooling costs had been met, would be much cheaper to produce and could never cause short circuits.

Both the TVTA and the TV1B used most of their power consumption for sound; the TV1A used about 100mW without sound which isn't all that much, though it could be used quite effectively as a torch. Although the TV1B had a one-inch speaker, it still used a lot of battery power for the sound; both sets were better if they were used with earphones.

The TV1B was finally launched in the autumn of 1978 at the Roof Garden of the Hilton in London. For the American market a VHF tuner was necessary; the one on the TV1A was insensitive so a new one was developed. This model went through its FCC tests and was called the TV1C. It went on sale in the US but not for long; for the TV to be a success a mass market was essential and this meant more than the UK or even the US, but Europe as well. In Europe there was a different sound frequency so the design of the TV1D was put in hand. Unfortunately, for reasons which we will come to later, the marketing effort was never sufficiently wholehearted for development costs to be recovered. Sinclair Radionics particularly needed the TV to be a success, because it was seen as the one product which had the potential to generate cash, for which Sinclair was now becoming increasingly desperate.