Very strange dekatron
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Greg S
Nov 22, 2025, 1:29:27 PMNov 22
to neonixie-l
Hi!
Do anyone know this type of dekatron? It has a very odd inside structure. With help of a CCFL driver I managed to know the pinout, and figured it out: It is a 40 electrode dekatron filled with possibly neon. Pins are G1, G2, G3, Anode, K0, and common cathodes (K1-K9). Finding place is Hungary, I only know an other collector to have this, also here. However we don't have any information about dekatrons were produced here ever. Also seems to be a prototype but not sure. There are no markings at all. Any help would be nice :)
Do anyone know this type of dekatron? It has a very odd inside structure. With help of a CCFL driver I managed to know the pinout, and figured it out: It is a 40 electrode dekatron filled with possibly neon. Pins are G1, G2, G3, Anode, K0, and common cathodes (K1-K9). Finding place is Hungary, I only know an other collector to have this, also here. However we don't have any information about dekatrons were produced here ever. Also seems to be a prototype but not sure. There are no markings at all. Any help would be nice :)
Dekatron42
Nov 22, 2025, 2:03:15 PMNov 22
to neonixie-l
Nice to see a new design!
Many many years ago i scoured patents and books for Dekatrons and other counting tubes and I have a very faint memory of a similar design in a Russian patent application. Maybe our Dekatron Guru Jon does have information on this one?
Any chance you can set it up to run and record a video to show us all?
/Martin
Jon
Nov 22, 2025, 3:05:15 PMNov 22
to neonixie-l
Wow! That's one I haven't seen before (and I've seen quite a few...). Looking at the construction, I think it probably is a prototype - it doesn't look like the kind of structure that is robust and well-controlled enough with respect to tolerances etc to be a commercial tube.
If you're interested to sell one, please PM me!
Jon.
Dekatron42
Nov 22, 2025, 4:57:16 PMNov 22
to neonixie-l
If Jon hasn't seen it it is indeed a rare one!
This would be something for Dalibor to start to develop, it seems like a very simple design just using Mica sheets compared to the moulded ceramics used in most production dekatrons.
/Martin
Greg S
Nov 27, 2025, 3:55:06 PMNov 27
to neonixie-l
Hi All! Thanks for your replies. I would be curious about that russian patent. Any chance to know in what book is that?
Finally I managed to build a spinner circuit for it parallel to find out what are the operational conditions. As it filled with neon, it was enough a voltage doubler in the power supply. I have 230V AC here, so the main anode voltage is ~410V DC in use. Measured right on the dekatron, striking voltage is ~170V, glowing voltage is ~130V. Current is ~180uA. It is fed with only 50Hz this way, so I don't know where could be its limit.
A short video here: https://youtu.be/yeCaUHqWLII
Greg
Finally I managed to build a spinner circuit for it parallel to find out what are the operational conditions. As it filled with neon, it was enough a voltage doubler in the power supply. I have 230V AC here, so the main anode voltage is ~410V DC in use. Measured right on the dekatron, striking voltage is ~170V, glowing voltage is ~130V. Current is ~180uA. It is fed with only 50Hz this way, so I don't know where could be its limit.
A short video here: https://youtu.be/yeCaUHqWLII
Greg
Jon
Dec 11, 2025, 5:53:14 AM (3 days ago) Dec 11
to neonixie-l
Thanks for the extra photos - that's really interesting. Great that you've got it working.
I've been doing a bit of digging in the dustier corners of my research archive, and think I'm onto the track of what this could be. Greg, I'll DM you with a couple of questions that might help confirm that.
Jon.
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