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Old 9th Feb 2021, 8:40 pm   #1
John10b
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Default Impact of Transistors.

I was reminiscing how the transistor impacted on my earlier working days in the domestic market and in particular in industry.
I can clearly remember the first time it occurred. In the inworkshop, which had about 20 technicians , we had to carry out preventative maintenance -PM - on many different types of electronic units, many which contained about 100 valves, the PM schedule was very strict and among other tests all the valves had to be removed and tested on the AVO valve tester. The was a lengthy procedure but it kept us busy.
Then one day the old units had been replaced with fully transistorised ones, well you can guess the conversation that took place, I can’t repeat some of the comments but needless to say it caused much debate.
The PM schedule simple called for such things as visual inspection, air filters cleaned, psu tested for regulation and ripple and full functionality, it did not require each transistor to be removed and tested!
Fortunately because of the nature of the industry many of the technicians were redeployed.
This is just my early memories of the first time transistors impacted on my working life.
I wonder what changes forum members faced in their early days?
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Old 9th Feb 2021, 9:44 pm   #2
G6Tanuki
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Default Re: Impact of Transistors.

I only got 'professionally' into electronics as a teenager in the 1970s: Two-way radio being my thing there were still loads of ~professionals~ in that segment who looked-upon transistor front-ends, solid-state receiver front-ends/IF-strips, transmitter modulators using bunches of NKT404 TO-3 Germanium transistors or HT-inverters using AFZ11 15-amp switching-transistors in things like Pye Vanguards and AM/FM Cambridges as some sort of voodoo.

They also had 'issues' with the whole idea of negative-earth batteries in cars. Talk to them about an all-transistor underdash-mount Pye Westminster (introduced in 1968) - which included heretical things like FETs as RF-amps/mixers - and they just didn't get it. As such, I poached quite a bit of business [using my father's line of business-credit and his business-name to buy stuff from Pye, even though I was under-21 and could therefore not legally enter into any contract based on credit].

This sort of fun paid my way through university - where I also learned about ICs and the first-generation microcomputers [Intel 8008/RCA1802].
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Old 10th Feb 2021, 11:17 am   #3
lesmw0sec
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Default Re: Impact of Transistors.

I recall a Mullard rep. saying how fed up he was being asked repeatedly "When can we get plug-in transistors"!
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Old 10th Feb 2021, 11:53 am   #4
David Simpson
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Default Re: Impact of Transistors.

Back in the 60's, the RAF was playing catch-up regarding semi-conductor training & info. Mainly due to the fact that at the start of the 60's all air & ground radio equipment just used valves.
As a trainee air wireless mechanic in 61/62, i reckon we only received a day or two's lessons on Ga diodes. Go forward a couple of years to my wireless fitter's course, 64/65, possibly a couple of weeks on basic theory(hole/electron pairs, etc) & another couple of weeks on practical circuitry,(OC71 flip-flops & such). Then one day on using a CT446, under strict supervision. Forward another year to 66, & off to Feltwell for a full week's "Transistor Course". In depth theory & a lot of practical circuitry work. Forward another 4 years to '70 - full circle, back to Cosford training school & ending up teaching practical transistor projects to apprentices, and the same (Feltwell school closed down) one-week transistor course for older trainees. Thankfully, the original outdated "conventional current flow" method of transistor theory had been dropped in favour of "electron flow". For the un-initiated - that's why electrons actually "flow" up the arrow head in transistors & diodes.
Forward another 50 years - a big collection of transistors/diodes/etc., 6 tr. testers, and a handful of early 1950-ish "Crystal Triodes" - commercial eq. of more or less the original Bell Lab's prototype transistor which started everything off!

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Old 10th Feb 2021, 12:47 pm   #5
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Default Re: Impact of Transistors.

As a long-time repairer of TV sets, I’d say the first major impact of transistors was their use in UHF tuners, which dramatically improved reception results with the (then) new BBC2 service. The much lower noise figure of the (Germanium) AF186 transistor knocked spots off the comparable PC88 + PC86 valve tuner.

In sets fitted with a valve UHF tuner, the addition of a “Labgear” (Pye group) transistor (line powered) masthead pre-amp - or even a set-side one - also improved matters greatly.
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Old 10th Feb 2021, 1:22 pm   #6
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Default Re: Impact of Transistors.

Agree the transistor UHF tuner made a huge difference in the ability to get a noise free or in some cases a picture for the new BBC2 service. Winter Hill started transmissions around the middle of 1965 just when some new sets were fitting transistor UHF tuners. We still had sets that had PC88 and PC86 valves but at least new sets didn’t have that problem.

Portable transistor radios also had lower battery consumption compared to the valve sets.
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Old 10th Feb 2021, 6:08 pm   #7
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Default Re: Impact of Transistors.

Quote:
Originally Posted by lesmw0sec View Post
I recall a Mullard rep. saying how fed up he was being asked repeatedly "When can we get plug-in transistors"!
I recall back in the early-70s showing an old-timer a PCB I'd produced, which was stuffed with around 20 7400-series TTL chips and 1488/1489 line-drivers, all firmly soldered in place.

"There's around hundred transistors in each chip!" I said proudly.

"What happens if one of the transistors fails?" he asked, and was horrified when I said you'd replace the whole board.
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Old 10th Feb 2021, 6:21 pm   #8
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Default Re: Impact of Transistors.

Back around 30 years ago I worked for Wharfedale. And of course loudspeaker crossovers had to be both designed and then manufactured in volume.

We had an old boy draughtsman, who insisted in drawing the crossover board as if it was a mechanical component, fully dimensioned copper tracks and including component hole diameters. With tolerances.

Nothing anyone said would encourage any other approach "you didn't design steam locomotives and bridges using any other than hand drawing, and this is no different"

It must have driven the board house bonkers, taking this painstakingly drawn diagram and converting it into a form that they could make in the tens of thousands for us.

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Old 10th Feb 2021, 7:23 pm   #9
duncanlowe
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Default Re: Impact of Transistors.

I was thinking, I had nothing I could add to this, as I've only ever dealt with transistorised stuff. A little bit of experience in the Germanium era but basically all silicon. I do remember my dad swapping valves in our dual tuner TV when they died, though that was done by looking for valves that the heater didn't glow.

But then I remembered my mate Eddie and a discussion we had. He was experimenting with electronics of all kinds when it was valves. He built a TV receiver from an ex WD scope of some kind. This was back in the day when Alexandra Palace was the only TV TX operating, even though he was based in the Midlands. He told me he was pleased that it worked, other than he wired one ste of scan coils the wrong way, so the picture was upside down. He and some friends also experimented with recording video on Swedish iron wire, but could never get the bandwidth as the fps needed yo be too high. He was really interested in how the problem had been solved with the rotating / scanning video head we all know and love.

But why is all of this relevant to this particular thread? Transistors had a massive impact on him. The whole (!) thing about the way they work, with holes transferring about, confused him and turned him off the subject (as to be honest it nearly did me). So he lost his interest when they came along which was a shame as he was a really clever guy.

I'm proud that he gave me his collection of a number of radio servicing and reference books from his youth, before he lost interest. They are lovely, but as I've never taken the time to get into pre-transistor technology are a lovely memory and no more.

I also think that transistors had an impact on teaching. For some time, they were taught as voltage devices. I guess that's because valves are largely a voltage controlled device (forgive my ignorance if I'm wrong on this). The first two times a teacher tried to teach me about transistors, they added resistors and talked about complex maths to give the voltage gain. It was only when someone explained it as a current device (IE collector current is a function of base current) and then moved on to explain the non linearity that I understood the whole thing. That's important because I came to spend my entire working life in the field of electronics, and now in my retirement, my hobby.
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Old 10th Feb 2021, 7:57 pm   #10
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Default Re: Impact of Transistors.

Considering the socioeconomic "impact of transistors" I'd also say that the late-50s/early-to-mid-60s coming of simple cheap-to-run portable transistor-radios [invariably using a 6-transistor lineup with a push-pull Class-B output stage] along with compact relativbely cheap-and-long-lived batteries [PP3/7/9] was significant.

These all made radio cheap and portable - perfect to tap into the emerging teenage market. Take it to the Brighton beach with you! Add in Luxembourg and the pirate-stations which emerged in the same timeframe, US-sourced Motown or first-generation Britpop [Beatles/Stones/Animals/Kinks] - and the "Trannie" really did democratize the world.

A whole generation grew up listening to the output of a pair of OC81s in push-pull !
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Old 10th Feb 2021, 11:31 pm   #11
Graham G3ZVT
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Default Re: Impact of Transistors.

Quote:
Originally Posted by lesmw0sec View Post
I recall a Mullard rep. saying how fed up he was being asked repeatedly "When can we get plug-in transistors"!
Sockets were always available, perhaps not from Mullard.

Many magazine construction articles recommended their use, you felt quite brave when you were confident enough to ignore that advice.

Most of the transistors in my Tektronix 453 scope, made in 1965 are socketed.

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Even the gold leads of the scan drivers on the LHS simply clip into those gold spring clips. So Even the likes of Tektronix didn't quite trust these three-legged interlopers, and treated them a bit like consumables, even though it must have impacted somewhat on reliability.

Not that Tek's reputation for dependability wasn't legendary despite this.
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Old 11th Feb 2021, 5:12 pm   #12
David Simpson
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Default Re: Impact of Transistors.

From what I remember from my Tr. teaching days, those wee sockets were used more for avoiding the heat damage done by heavy - handed technicians with the basic old lumpy soldering irons many were still using from the 40's & 50's. Yep, copper bitted crock-clips(heat-sinks) were made by many of us in the early to mid 60's, but for short - leaded components they were difficult to use.

Regards, David
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Old 11th Feb 2021, 5:26 pm   #13
G6Tanuki
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Default Re: Impact of Transistors.

I think another significant impact of transistors was the reduction in need for repair techs!

All-valve tellies from the 40s and 50s were always going wrong and needing a technician to visit; the coming of transistors meant that tellies ran a lot cooler and were much more reliable.

Sony boasted about this in their ads for the first Trinitrons.

A typical 1950s valve TV might have needed several service-visits per year, by the 70s it was quite normal for an all-transistor TV to live its typical 7 or 8 years service-life without ever needing any form of service attention, so freeing-up the technicians to concentrate on more-profitable work.
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