hello all...hope the holidays find you well.
I have a nice big globe UX280 rectifier tube that the filaments light, but shows zero emission, and zero gas. (no shorts though) Prior owner says it looks like a firework show in a set. Is there any way of possibly repairing a tube like this? or finally dead after 80 years of service? I also have a 226 that will work if I wiggle the tube in its loose base.....

Hi

Might try resoldering pins. If the prior owner says it looks like fireworks tube is probably gassy. It may not show up on a tube tester due to low voltage available. In an actual circuit voltage may reach 350..

Norm

:hello all...hope the holidays find you well.
:I have a nice big globe UX280 rectifier tube that the filaments light, but shows zero emission, and zero gas. (no shorts though) Prior owner says it looks like a firework show in a set. Is there any way of possibly repairing a tube like this? or finally dead after 80 years of service? I also have a 226 that will work if I wiggle the tube in its loose base.....
:

If you can see a purple gassy glow within the tube while it is in operation, then the tube is gassy. If you can knowingly increase the plate current and voltage in your tube tester, you may be able to simulate something close to what the tube would experience in a radio.

If there was a fireworks display within the tube, I am guessing that the oxide was stripped from the filament. This could have been due to a short in the radio, and would reduce the emission of the tube to near zero. The tube should still have some emission, though, however slight. I would check solder connections, as Norm said, and also check to see if the lead wires have burned through in the tube base.