01-10-2019, 06:23 PM
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
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
