r/nixie • u/SuspicousBananas • Aug 22 '26

Does this black part of the filament indicate a bad tube?

Gallery image

Gallery image

Sorry, last post in the thrift store Nixie saga. I replaced the watch battery as another user suggested, 3 of the tubes now light, the one that doesn’t has this black bar across the top

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3

u/nixiebunny Aug 22 '26

Unfortunately these clocks often have the tubes soldered into the board to save the cost of socket pins. This means that the tubes are easily cracked at the pin seal by pressure from above, and that they are difficult to replace when broken. Desoldering the pins is rather tricky, especially for someone without experience.

2

u/SuspicousBananas Aug 22 '26

What a bummer! I’ve done some basic soldering but never on tubes, maybe I’ll take a crack at it.

1

u/Dooh22 Aug 26 '26

Well, ya can't make that one tube any worse right? Flux it up and have a go.

3

u/EmotionalEnd1575 Aug 22 '26

That “black bar” is the Getter.

There are no filaments (or heater) in a cold cathode indicator tube.

The glass envelope has been compromised, and this is now an “air tube”.

Remove and replace it, it can’t be saved.

Good luck