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37-690 rectifier flash / arc
#1

Hi,

I'm not brand new to this, but I'm not a trained technician either. I waited to rebuild 40-50 radios before tackling this project. After a full recap of paper and electrolytic capacitors, testing of tubes, field coils, transformers and anything else I could think to check, this is what happened.

Initial power up using my variac gave me (I believe all) filiments lit, I think I heard a power hum from the main speaker, but no reception at all, and no differences when I changed the band switch. After perhaps a couple of minutes at 115v, I saw a flash/arc from one of the rectifier tubes (running 5Y4G instead of 5X4).  I shut it down instanty - nothing felt hot or even warm. The rectifier in question was now dead. 

I took both chassis back to the workbench and after retracing my work, made a couple of small changes, rechecked coils, and tried again with another NOS tube - only to have the same results.

Any thoughts on troubleshooting or isolating this problem would be greatly appreciated.

Chris


Messages In This Thread
37-690 rectifier flash / arc - by mr.jukebox - 01-10-2019, 07:23 PM
RE: 37-690 rectifier flash / arc - by Ron Ramirez - 01-10-2019, 07:47 PM
RE: 37-690 rectifier flash / arc - by Phlogiston - 01-10-2019, 07:54 PM
RE: 37-690 rectifier flash / arc - by mr.jukebox - 01-10-2019, 08:05 PM
RE: 37-690 rectifier flash / arc - by Ron Ramirez - 01-10-2019, 08:06 PM
RE: 37-690 rectifier flash / arc - by morzh - 01-10-2019, 09:16 PM
RE: 37-690 rectifier flash / arc - by tbone - 01-12-2019, 07:32 AM
RE: 37-690 rectifier flash / arc - by 35Z5 - 01-12-2019, 06:25 PM



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