I was given a beautiful 32B power DHT (300B on steroids) with a broken filament. I don't know the story behind the failure, but the DVM tells me that the filament is broken (no connection between the filament pins). It would be nice to rescue that broken tube. Any chances to repair that? Anyone out there doing this kind of stuff?
(Yes, I understand that this will not be trivial given the vacuum tech, glass blowing, and getters involved -- but you never know...)
(Yes, I understand that this will not be trivial given the vacuum tech, glass blowing, and getters involved -- but you never know...)
There were still companies that repair tubes ten years ago. But we are talking ultraexpensive big specialty radar tubes and the likes. Just getting a new pair of 300BXLS might be easier and cheaper.
This chap can do it, have a look at his YouTube content.
https://www.youtube.com/results?search_query=glasslinger+website
https://www.youtube.com/results?search_query=glasslinger+website
Is it visibly broken?
In this case it will be only display tube.
Sometimes the thin wire (from the filament fastening/welding to filament pin in socket) soldering not perfect (to let go) and resoldering helps.
In this case it will be only display tube.
Sometimes the thin wire (from the filament fastening/welding to filament pin in socket) soldering not perfect (to let go) and resoldering helps.
If it's VV32B, on the upper mica four metal "spring" strain the filament wire. If they are not evenly tightened, the wire probably broken.
Aargh, yes, one is protruding more than the others. Oh well.
I might ask Emissionlabs, they did these repairs in the past. Not sure if they still do it.
I might ask Emissionlabs, they did these repairs in the past. Not sure if they still do it.
I have resoldered pins before. It's a little tedious and you need a lot of heat. I have some very rare Speed 295 twin triodes and one would not work. I removed all of the old solder with a vacuum, scraped the wire and inner pin surface as much as possible and added a lot of flux. I heated the pin from the outside and when it was quite hot, applied solder. It takes quite a bit. The tube is still working.