A solid state replacement for the lowly 2D21 Thyratron tube...(sorry for the On-Topic post!)

John Robertson · 2021-04-21T17:28:02+00:00

In my field of arcade repairs we run into older jukeboxes - one particular model which uses the 2D21 tube and was from about 1954.I have the spec sheet here: would be fun to make a solid state replacement for it as nothing seems to exist. These tubes are still available from several sources, but they get wonky with age.Being able to simply wire in a TRIAC or SCR (with appropriate bits of electronic glue) to remove this tube from the suspect list when servicing this classic Seeburg V200 jukebox would simplify future servicing. I always like to make things easier for the next tech to work on machines that passed through my shop...I should point out that Seeburg only used these 2D21s (three 2D21s used) on their very first control center for their Tormat (200 x magnetic cores) memory and dropped it like a hot potato. There were numerous service bulletins culminating in the factory providing a low cost replacement for the control centers that used 2D21s (three of these) and the replacement used a single 2050 tube and was a very reliable design. Not everyone took advantage of the program and all these replacement were used up long, long ago.John :-#)#

Apr 21, 2021 Last reply: 5 years ago 67 Replies

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DecadentLinuxUserNumeroUno 5 years ago

bitrex snipped-for-privacy@example.net wrote in news:hYegI.69395$ snipped-for-privacy@fx45.iad:

Your pschologist attitude is not matched by your education. Stay out of the personal assessment opinion crap.

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bitrex 5 years ago

Have you given your inner child a hug today, though

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John S 5 years ago

So neon lamps don't die, they just sputter away?

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John S 5 years ago

So neon lamps don't die, they just sputter away?

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Tauno Voipio 5 years ago

The device was an ATCR-33K ait traffic control primary radar by Selenia, in late 1980's. Its power was max. 1.5 MW per channel.

It was decommissioned at the end of previous millennium.

I'll look if I still have some manuals left, memory does not serve too well for so old things.

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jlarkin 5 years ago

Good line. Please post it a few more times.

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John S 5 years ago

No. You are welcome to use it.

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Joe Gwinn 5 years ago

They still make ATCR-33 radars, now at rev S or so. All solid state.

I was in ATC radars and automation systems in the 1980s, but never ran into mercury-tube thyratrons in modulators, probably for the same reason that SCRs were not much used - how do you turn them off in preparation for the next pulse? (The duty cycle is about 1%.)

But who knows what the Transmitter folk were up to.

So luck must serve.

Joe Gwinn

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