Brian in 1972, not long after starting work at Sinclair Radionics
By the time I left Sinclair Research, the ZX80 was on sale and I was working on its successor, the ZX81, which involved reducing the number of low-power Schottky TTL chips and putting them into one programmable IC – an uncommitted logic array – which was made by Ferranti. There was something like ten TTLs in the ZX80, which all had to be reduced into one IC. That all went ahead and meant that, because fewer components were inside the ZX81, it was more cost-effective than the ZX80. My job at that point was to help with the engineering and check that it was going to work.
When I joined the company was called Sinclair Radionics and was in Enderby’s Mill in St Ives. My position was Electronics Design Engineer, and I worked in R&D. I got the job because I had experience in television design from working at Pye/Philips in Lowestoft, and virtually the first project I was put on at Sinclair Radionics was the development of a miniature television set.
At that time the only products they had on sale were hi-fi products, including a stand-alone FM tuner, a power amplifier and some kits. The kits comprised components which people could fit into the plinths of a record player to add a preamplifier or whatever it might be. The record players at that time usually came with a wooden plinth so you would cut holes in the plinth and bolt these bits and pieces on the front. Believe it or not, that’s what people did! Apparently there was a market for that, although not much of one, I suppose. The company sold a stand-alone amp as well, just to cater for a different market.
Early Days at the Mill
I joined Sinclair Radionics immediately after leaving Pye/Philips. Pye/Philips was a large company and I just didn’t see myself carrying on there. I felt that I needed to get into design with another company. The job I originally applied for wasn’t at Sinclair Radionics, but with another company who were based elsewhere in the St Ives mill grounds and made some sort of instrumentation.
I went for an interview but didn’t get the job. I thought that was the end of it, but then I was contacted by Clive Sinclair asking if I’d like to come for an interview with him. I’d got the first interview through a recruitment agency called Cambridge Recruitment and he must have found out about me from them.
Sinclair had noticed that I had experience in colour television set design working for a major TV manufacturer. He was developing his own television set so he was on the lookout for anyone who could be useful. Although I was still a pretty young engineer – about 25 years old –I already had a certain amount of experience having started working at Pye’s when I was 15. He interviewed me personally, we had a chat and that was it, I got the job. I must have said the right things.
When I joined there were about four other electronic engineers there already. There was John Nichols who eventually left and formed Thurlby Thandar Instruments. Thurlby and Thandar were separate companies that originated from Sinclair Instruments when the company broke up in about 1978, but they still had links with Sinclair. Thurlby and Thandar eventually combined and changed their name to TTi.
Then there was Chris Curry, who later formed Acorn, Jim Westwood, who’s a very good practical design engineer, and another chap called Keith Pauley, who left in about 1973 and is now a Production Director at TTi. Plus there was the chief engineer, and my immediate boss, Martin. He was there from about 1970 to 1973, then left to work for an audio manufacturing company making power amps and quadraphonic amplifiers, but I don’t think they lasted long.
It was a very young team; we were all kids really. Jim Westwood is younger than I am; Chris Curry is about the same age, as is Keith Pauley. Martin was about five years older, possibly in his late 20s, and Sinclair was in his early 30s. All of those people were doing electronics to some extent, but there were other departments, including accounts, stores and various people in the test department downstairs.
Our R&D department was on the top floor, as was Clive Sinclair’s office, which was at one end overlooking the river. The upper floor had these cubicles set up, with a door, two benches inside and a window. Me, Keith, Chris Curry, and possibly John Nichols, were crammed in one of these, which was only a few meters across. Martin was in another one on his own.
It wasn’t compulsory, but for a while after I joined we used to wear technician’s white lab coats to protect our clothes, and the company had a laundry system where they would all be collected and washed at the end of the week.
Some of the floors were not occupied at that point, but filled up a couple of years later when the company grew. The first time I saw someone cycling around on an early C5 prototype was on the top floor of the mill and would have been within a year of me joining the company. I didn’t realize that what I saw was eventually going to turn into a car!
When I joined the main product was the hi-fi equipment, but some design work on the miniature television set had already been going on. There was a set of IC chips that had been designed for it which we were waiting to come in from Texas Instruments. They were the company who were manufacturing the chips for us.
I’m not quite certain who’d designed the ICs. Maybe some of it was done by Sinclair himself, or possibly an engineer at Texas Instruments. Whatever the case, the television’s next stage of development was dependent on this set of three or four ICs arriving.
Sinclair Radionics were also developing their own cathode ray tube for the TV, which they were having made by a little factory in South London. There was a chap down there who was helping organize a small prototype production run and he sent bits and pieces to us.
Those tubes were unusually shaped like a coffin, but we had problems with the vacuum inside. If you get a few parts-per-million of air inside a tube, when you put high voltages on it – I’m talking about one or two KV – the air becomes very conductive, like a piece of copper, and causes the thing to short out! All the ions shoot down the tube, it flashes over and blows up all the semi-conductors, and that happened when I was testing it.
I’d painstakingly built all these little frame and line oscillators and EHT circuitry to go around the tube and had been working on it for weeks when one of the coffin tubes arrived. I very tentatively connected it up to the tube and as soon as the EHT 2KV was applied it flashed over internally and blew up all the transistors and half the board.
The lot went in one go. It was a bit of a set back and I’d only just joined the company. As time went on I learnt that if we had a tube that was likely to flashover, it was good practice to put protection resistors in the circuit at various places so that it could withstand the flashover – but when I first started I didn’t appreciate that such a thing could happen. I think I had a bad moment over it and might have almost walked out. I can’t remember exactly, but I was pretty upset!