Early Electronics

[Muhendis]

As we progress up the endless road of.........progress, we (I) find ourselves getting forgetful of where it all started.

Fixing crystal radios so you could almost hear the light program.

Making that first amplifier with transformers and valves.

Figuring out how to solder wires to valve basses.

wondering why heaters were 6.3v.

 

Can you remember your old valves?

 

I can and what's more they are still in production. take a look:-

https://brimaruk.com/valves/brimar-tube-range/

 

 

 

[asf6]

I can remember enjoying watching a mercury arc rectifier do its thing. It looked something like this. 

 

 

[Muhendis]

  On 6/13/2023 at 12:29 PM, asf6 said:

I can remember enjoying watching a mercury arc rectifier do its thing. It looked something like this. 

 

 

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Me too. It was part of the power supply for the punched card computer system in the CWS building in the centre of Bristol.

Mechanical card readers and valve computer.

[Muhendis]

  On 6/13/2023 at 12:29 PM, asf6 said:

I can remember enjoying watching a mercury arc rectifier do its thing. It looked something like this. 

 

 

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Didn't those things need special X-Ray proof enclosures?

[OneMoreFarang]

Mr Carlson's Lab - YouTube

[Muhendis]

There's a video showing well dressed shopfloor workers making valves.

Must be from the 1940's

https://brimaruk.com/valves/brimar-tube-range/

[asf6]

  On 6/13/2023 at 1:44 PM, Muhendis said:

Didn't those things need special X-Ray proof enclosures?

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I don't know. I've never heard that before. The one I had access to was in an enclosed metal cabinet. Nobody ever mentioned anything about it being X-Ray proof. Was the one you had access to enclosed in an X-Ray proof cabinet? 

[Muhendis]

  On 6/13/2023 at 3:01 PM, asf6 said:

I don't know. I've never heard that before. The one I had access to was in an enclosed metal cabinet. Nobody ever mentioned anything about it being X-Ray proof. Was the one you had access to enclosed in an X-Ray proof cabinet? 

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i just did a quick google.

X-Ray was the story I was told at that time, and it turns out to be true but only for voltages in excess of 16kv. 

Protection from external magnetic and rf fields is important for longevity and interference proofing.

[Crossy]

Yeah, we had one of those beasties in the Machines lab at Bath tech. Main safety hazard (apart from getting zapped) was the massive amounts of UV emitted, hence the steel box.

 

Memories of Mr (Fray Bentos) Bentley our Machines lecturer, now long gone. Hated calculators (which were just appearing) "Monkeys can push buttons!". But he did teach me everything I've ever forgotten about AC theory.

 

EDIT The man himself.

Sadly, it was getting knocked off his bike that led to his declining health, he was never quite the same man afterwards.

 

 

 

[Crossy]

Fresh out of uni, newly married and poor I used to buy up ex-rental TVs from a place in Chepstow, re-furbish them and sell on for a profit. Quote from a mate "I saw all these TVs coming across the Severn Bridge with a little Fiat underneath, I knew immediately who it was...".

 

Earliest sets I did in quantity were Philips G8 (this one is missing the line scan board, should be on the right).

 

[Muhendis]

  On 6/14/2023 at 12:32 AM, Crossy said:

Fresh out of uni, newly married and poor I used to buy up ex-rental TVs from a place in Chepstow, re-furbish them and sell on for a profit. Quote from a mate "I saw all these TVs coming across the Severn Bridge with a little Fiat underneath, I knew immediately who it was...".

 

Earliest sets I did in quantity were Philips G8 (this one is missing the line scan board, should be on the right).

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That'll be when the bridge was free

 

I used to do the same with KB TV's

 

Where's the turret tuner in that picture?

[Crossy]

  On 6/14/2023 at 1:23 AM, Muhendis said:

Where's the turret tuner in that picture?

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The G8 had an electronic push-button tuner, that drifted like heck if the voltage regulator that fed the varicap went awry. It often didn't actually fail, just went off-tune when things warmed up. Nightmare!

 

This is what it looked like to "normal" people ???? 

 

[treetops]

  On 6/14/2023 at 12:32 AM, Crossy said:

Earliest sets I did in quantity were Philips G8 (this one is missing the line scan board, should be on the right).

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I made these boards as an apprentice, although I can't remember the rest of the names.  Perhaps an RGB and a Line/Frame Sync and maybe one more.

 

70,000 tuners per week too, where the wobbulators in the testers needed calibrated every  morning.

 

We rejuvinated a few CRTs on the side on occasion too which was fun.

[Muhendis]

  On 6/14/2023 at 5:45 PM, treetops said:

I made these boards as an apprentice, although I can't remember the rest of the names.  Perhaps an RGB and a Line/Frame Sync and maybe one more.

 

70,000 tuners per week too, where the wobbulators in the testers needed calibrated every  morning.

 

We rejuvinated a few CRTs on the side on occasion too which was fun.

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Not sure about "wobulators in the testers" but there was such a thing as a wobulator which had the job of making the spot wobble as it traversed the screen.

The idea behind that was to try and fill in the gaps between each of the 405 lines. Which were quite noticeable on a 21" screen.

 

I managed to wreck a few CRT's by "rejuvenating" them. Zapping the cathodes to release a few more electrons worked mostly and could put off buying a new tube for a few months.

 

A friend of mine, aged about 20 at the time, fancied himself as a TV repairer and was given a 21" B&W TV to fix. It had a series connected heater chain driven through a mains dropper and no heaters were showing. Safe in the knowledge that the tube heater was at the high end of the chain, he decided to connect the other end of the mains to the dead side of the heater. For about half a second the cabinet was flood lit fantastically.

The owner was quite forgiving since it was an old set and my friend decided on a different career direction.

[Crossy]

  On 6/14/2023 at 11:30 PM, Muhendis said:

Not sure about "wobulators in the testers" but there was such a thing as a wobulator which had the job of making the spot wobble as it traversed the screen.

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Wobbulator in this case was a piece of kit used to align IF strips. It produced what was effectively narrow-band FM, tune the cores for maximum smoke ???? 

 

https://en.wikipedia.org/wiki/Wobbulator

 

This is a military one but you get the picture ???? 

 

 

[lopburi3]

We called them tubes in the new world.  And normally had removable sockets to hold them so not solder to actual tube.  These transmitters had a lot of glowing tubes presenting a danger if door interlock failed.

[Crossy]

  On 6/15/2023 at 1:44 AM, lopburi3 said:

We called them tubes in the new world.

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"Bottles" old bean, bottles

[Muhendis]

  On 6/15/2023 at 1:17 AM, Crossy said:

 

Wobbulator in this case was a piece of kit used to align IF strips. It produced what was effectively narrow-band FM, tune the cores for maximum smoke ???? 

 

https://en.wikipedia.org/wiki/Wobbulator

 

This is a military one but you get the picture ???? 

 

 

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Aah yes.

A sweep generator. Didn't use them much. Simply screwed the cores up and down a bit 'till you got better undistorted sound or 'till the core shattered.

 

Did a lot in connection with SAWF (Surface Acoustic Wave Filter) in the early 70's which replaced IF strips in TV's 

[lopburi3]

  On 6/15/2023 at 1:47 AM, Crossy said:

 

"Bottles" old bean, bottles

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Had to look that up - from New England so only know half English.  ????

[Crossy]

Second-year apprentice project (not mine, it's long lost), MW superhet radio. IF cans were deliberately de-tuned by the lecturers so we had to manually align.

 

No sweep generators, just a massive Marconi RF signal generator.

 

First task once completed, turn it into a transmitter of course!

 

[sandyf]

  On 6/13/2023 at 12:17 PM, Muhendis said:

Can you remember your old valves?

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Never to be forgotton. In the mid 60s I was trained on thermionic valves, magnetic amplifiers, differential transformers, infinitely variable gearboxes, analogue computers etc. Stuff that most in the electrical world have never heard of.

Worst electric shock I ever had was from a 450v DC HT lead, blown off the stool and a quarter inch deep hole at the point of contact.

[Tippaporn]

  On 6/14/2023 at 12:32 AM, Crossy said:

Fresh out of uni, newly married and poor I used to buy up ex-rental TVs from a place in Chepstow, re-furbish them and sell on for a profit. Quote from a mate "I saw all these TVs coming across the Severn Bridge with a little Fiat underneath, I knew immediately who it was...".

 

Earliest sets I did in quantity were Philips G8 (this one is missing the line scan board, should be on the right).

 

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Back in '02~08 I lived in Huai Khwang right across from Fortune Town.  I recall an audio boutique, I believe it was (and maybe still is) on the ground floor, which sold stereo tube amplifiers, pre-amplifiers, and other hi-end audio components.  I was always curious but regrettably never went into the shop.

I'm an illiterate on this subject but what would be the advantage here?  Does it enhance audio quality?

Just an example.  They are works of art, to say the least.


 

[Tippaporn]

  On 6/15/2023 at 2:25 AM, sandyf said:

Never to be forgotton. In the mid 60s I was trained on thermionic valves, magnetic amplifiers, differential transformers, infinitely variable gearboxes, analogue computers etc. Stuff that most in the electrical world have never heard of.

Worst electric shock I ever had was from a 450v DC HT lead, blown off the stool and a quarter inch deep hole at the point of contact.

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I don't mean to laugh at your unfortunate incident but it was the thought that the shock on your face must have been greater than the electrical shock itself. 

[sandyf]

  On 6/15/2023 at 2:02 AM, Crossy said:

Second-year apprentice project

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Our final year project was to build a basic oscilloscope. One team conected a fairly large electrolytic capacitor the wrong way round. When switched on it was like a snowstorm had hit the training room.

[Muhendis]

  On 6/15/2023 at 2:28 AM, Tippaporn said:

Back in '02~08 I lived in Huai Khwang right across from Fortune Town.  I recall an audio boutique, I believe it was (and maybe still is) on the ground floor, which sold stereo tube amplifiers, pre-amplifiers, and other hi-end audio components.  I was always curious but regrettably never went into the shop.

I'm an illiterate on this subject but what would be the advantage here?  Does it enhance audio quality?

Just an example.  They are works of art, to say the least.


 

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Yes they are the connoisseurs choice, and price too for that matter.

Available on line.

 

The only thing I can say about valve sound is that the distortion is such that some things actually sound better to some people.

[Crossy]

  On 6/15/2023 at 2:28 AM, Tippaporn said:

I recall an audio boutique,

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Was that The Analog Shop? Not sure if it's still there, but there's certainly a place in Zeer doing the same type of kit. If you have to ask the price - you can't afford it ???? 

 

There are many explanations for the "valve sound", they certainly sound different.

 

They "clip" gently and the distortion is second-harmonic which is less grating than the third-harmonic that bipolar transistors produce. FETs are similar to valves in producing second-harmonic distortion but they still clip hard.

 

All very subjective.

 

[h90]

I run here CNC lathes with technology from the early 1990s....not tubes but still a hassle to get them repaired

[Muhendis]

There used to be a factory in Bedminster, Brislol called Will's which made Will's Woodbine cigarettes. The first floor was taken up by a huge valve computer programmed by thousands of punched cards. Those valves had to be frequently swapped and tested on an AVO valve tester and valves below par were placed in the reject box.

I had quite a few of them which were good enough for my various amplifier projects.

 

 

Incidentally the heat from the valve computer was ducted around the factory to keep the workers warm.

[Robin]

Still at school when I started with "electronics".  No money to buy parts so we collected ex-rental TV chassis from local hops.  Given away free!  some we could repair and pass on, others wee a source of parts for experiments.  Somehow, I picked up enough knowledge to get a job at EMI and then....

Things were easier o fix then ?  

 

[dddave]

  On 6/15/2023 at 1:44 AM, lopburi3 said:

We called them tubes in the new world.  And normally had removable sockets to hold them so not solder to actual tube.  These transmitters had a lot of glowing tubes presenting a danger if door interlock failed.

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My dad was an avid "Ham" radio enthusiast. (K1CNW)  One of his happiest days ever was when he purchased, then set-up a 2nd hand Collins receiver, the Holy Grail for hams of that era, that another ham was selling.  He was a clergyman and IIRC, he wore his clerical collar to the transaction, hoping it would assist in knocking a few dollars off of the price.

 

Old calculators have been mentioned.  One of my favorite lifetime moments was when I quit and walked-off one of my most odious jobs ever; doing time and motion studies then production rate settings for piecework workers winding coils in an electronics factory. It was a terrible job as I was loathed by everybody. The workers angry, convinced I set rates too high, management convinced I was in league with the workers and setting them too low.

 

The calculator occupying a third of my desk was a huge, ten rows by ten columns of keys, mechanical monster that operated on revolving cams to complete calculations which could stretch on for several seconds or more, depending on complexity: "ka-ping-ka-chung-ka-ping-ka-chunk"

One day, as some assistant to the assistant manager berated me yet again for some algebraic transgression, I decided I'd had enough. I got up and in as many words, told him to stuff-it.

Just before leaving for the manager's office to quit, I entered the highest number possible: "9999999999" into the calculator, then divided it by ".0000000001".

The manager was still angrily shouting at me as I walked past my office on the way out.  There was a small cluster of assistant managers gathered around my desk, all with perplexed faces:

"ka-ping-ka-chung-ka-ping-ka-chunk-ka-ping-ka-chung-ka-ping-ka-chunk............."