The A201 isn't a dekatron, it's a polyatron, which has a central cathode with surrounding anodes. You're running it in reverse polarity, the glow should be in towards the center of the tube, rather than out on the anodes.
Hi Vintage Tech. Folks! Love your web site and your videos. You are correct, of course that I am running this reversed. It looks really cool this way and I don't think it will harm the tube (please correct me if I am wrong). Can you tell me what pin 9 is for? I left it disconnected.
We have also ran them in reverse polarity, it doesn't seem to harm the tube, at least in the short term. I don't have the datasheet in front of me, but I think pin 9 is attached to some sort of control grid which we suspect may be used for digit blanking. The A201 was intended as a Nixie driver, thus having non-direct viewability, slow speed and polyatron polarity. The extra pin will indeed extinguish the glow, so digit blanking seems like an obvious function.
The A201 isn't a dekatron, it's a polyatron, which has a central cathode with surrounding anodes. You're running it in reverse polarity, the glow should be in towards the center of the tube, rather than out on the anodes.
hp2114b 2 years ago
Hi Vintage Tech. Folks! Love your web site and your videos. You are correct, of course that I am running this reversed. It looks really cool this way and I don't think it will harm the tube (please correct me if I am wrong). Can you tell me what pin 9 is for? I left it disconnected.
mjrippe 2 years ago
We have also ran them in reverse polarity, it doesn't seem to harm the tube, at least in the short term. I don't have the datasheet in front of me, but I think pin 9 is attached to some sort of control grid which we suspect may be used for digit blanking. The A201 was intended as a Nixie driver, thus having non-direct viewability, slow speed and polyatron polarity. The extra pin will indeed extinguish the glow, so digit blanking seems like an obvious function.
hp2114b 2 years ago
Yes, grounding pin 9 in my setup did extinguish the glow so that makes sense. Thanks again!
mjrippe 2 years ago