On another forum, I posted a picture of a motor my Father made with spare parts. Then I thought to myself, where did they get parts? I think RCA and G.E. made vacuum tubes.

Mouser was formed in 1964 and Digikey was formed in 1972. Radio Shack was formed in 1921.

What was there before then?

I looked at the History of Electrical Engineering before then and it lacks the history.

http://en.wikipedia.org/wiki/History_of ... ngineering

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What's an additional VIA among friends, anyhow?

I was buying stuff from Allied and Newark in the late 1950s, all tubes of course. There were no Radio Shacks in our area. Allied continued to stock receiving electron tubes (valves) up until at least the latter 1980s, all American, British and German brands. They also stocked some commercial tube types, such as the 803 and 807, which we used in home-built ham radio transmitters.

Ah, the good old days when a stereo amplifier helped to keep the living room warm in the winter.

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x86?  We ain't got no x86.  We don't NEED no stinking x86!

You might enjoy this very short video from London's Science Museum:
Information Age: The radio transmitter that changed our world
(They've just opened a new gallery - there's also a video about LEO, the first business computer, and there's a series of short radio programs too.)

See here for more details about the exhibition.

Cheers
Ed

LEO was an amazing breakthrough. Who would have thought that a cake company would rig up something like that? Even more amazing was the extent to which LEO automated the Lyons company's daily operations. Considering how primitive the hardware of the time was, as well as the lack of programming tools, it was a major feat to get the system up and running.

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x86?  We ain't got no x86.  We don't NEED no stinking x86!

I firmly recommend Georgina Ferry's book:
http://www.ianhopkinson.org.uk/2012/07/ ... ina-ferry/

Thanks, Ed -- definitely some interesting content there. Over and above that, I can't help being impressed with the upbeat animation techniques used in the videos -- particularly the one about LEO. It's remarkable how much they've managed to enliven the source material (which consists mostly of still images).

As for parts sources, like Garth I remember the neighborhood Mom & Pop surplus/electronics stores, and also Allied and Lafayette. The latter were even more problematic for me than for Garth, due to border & customs issues, but that didn't stop me from poring over their catalogs and dreaming up problems for the solutions they contained! Those catalogs served both for inspiration and as an educational resource.

Another major source of parts for me was discarded TV sets, which in my teen years were black-and-white models powered by vacuum tubes. The easy pickings included tubes and transformers, but I also amassed a collection of resistors & capacitors which, according to the style of the day, had been hand-wired point-to-point on phenolic terminal strips. (No printed-circuit boards in these sets!) Of course only an over-zealous teenager would've bothered salvaging carbon composition resistors & paper-dielectric capacitors -- and selenium rectifiers! The stuff was junk, and had little value even when new.

OTOH I have no ambivalence about my decades-old collection of vacuum tubes. Definitely worth keeping! Some of those tubes are used in vintage audio gear -- for example, my brother's Hammond organ... and BDD's Ampeg bass amplifier (a few years ago I sent 'im a pair of well-seasoned 6SL7 twin triodes)!

cheers
Jeff

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In 1988 my 65C02 got six new registers and 44 new full-speed instructions!
https://laughtonelectronics.com/Arcana/ ... mmary.html

And they're still on the job. Can't say the same for the Russian 6L6GCs—those are good for about 9 to 12 months of service before they start to lose steam. I used up the last of my NOS 6L6s about five years ago. The ones that are still available go for big bucks, and are suspect, as some will gas out after a few hours of hard use..

_________________
x86?  We ain't got no x86.  We don't NEED no stinking x86!

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

Some nice details in that article about selenium rectifiers - thanks Jeff!
http://en.wikipedia.org/wiki/Selenium_r ... eplacement

In the 70s there were independent (Mom & Pop) TV shops (stores) which had surely grown out of radio - they would do repairs, and rent out equipment, and sell refurbs pretty cheap. I bought at least a couple big black & white sets (valve-based) which got some use as computer monitors. People were moving to colour TV of course.

A few years earlier I remember a tiny little shop where I bought roll film for my Brownie. It wouldn't surprise me if that place also dealt with spares for radios.

Selenium rectifiers can still be spotted nowadays in booster/chargers for car batteries, but AFAIK all their other applications have disappeared. The unit above is one of a pair, fed by a very hefty center-tapped transformer.

At the other end of the spectrum -- more brain than brawn -- it appears selenium rectifiers, like silicon diodes, have been used as logic elements. I wish I had more info to provide, but the photos below show the partially scavenged carcass of some sort of automatic billing or accounting machine that was given to me ages ago. I surmise that the rectifiers (the green plates) were wired together to serve as OR gates, with the outputs going either to relay coils or to solenoids in an attached printer. The "logic" supply was probably unfiltered and unregulated 90 VDC, obtained via a bridge rectifier fed directly from the 120 VAC mains.

There's a Wikipedia page for the manufacturer, Friden, here.

There's another Friden machine which I learned much more about -- in fact, I hacked it! Back when I was a beginner I had a Friden Flexowriter which I managed to interface to my first computer, a MOS KIM-1. The Flexowriter was my first printer. Later I bought a wide-carriage, state-of-the-art dot-matrix (!), but it was the Flexowriter which first allowed me to generate hard copy computer output. What's more, I could do paper tape, too!

cheers
Jeff

_________________
In 1988 my 65C02 got six new registers and 44 new full-speed instructions!
https://laughtonelectronics.com/Arcana/ ... mmary.html

A picture of horror and a picture of beauty! Excellent.

Yep! The electrical controls on some older railroad cars and even some locomotives used selenium rectifiers in that way. I also ran into that sort of application in automatic block signal logic.


Looks like the rats got to the wiring.


When I was going to electronics school at Great Lakes Naval Training Center (north of Chicago), I was introduce to the Friden Flexowriter. This one was connected to a ballistic computer, which was all tubes. The Flexowriter was the main competitor to the Tele-Type model 33 and was used by the U.S. Navy in some shore installations. The 33 was based on a design originally developed for the U.S. Navy, with the mechanism sufficiently ruggedized to withstand the shock and vibration caused by firing the main guns. We had two such TTYs in the radio room and almost enough parts in stock to build a third one.

_________________
x86?  We ain't got no x86.  We don't NEED no stinking x86!