12-25-2017, 12:36 PM
For those of you who are watching at home after several phone calls and digging into the schematic we found that this HV distribution is wired slightly differently than the schematic. There was another wire connected to C-37C feeding the 1st and 2nd IF amp's plate voltage. Schematic shows this wire connected to C-37B.
The problem ended up being a low resistance path across T-10 the 1st IF transformer. From pri to sec was about 1.5K this applied + 200vdc to the control grid 1st IF amp tube V-2. It didn't like that! Caused the tube to draw excessive plate current pulling the HV down.
I'm thinking that the two fixed caps in the IF can are shorted from silver migration, but that is yet to be seen. We do know that the IF transformer has resistance from pri to sec which it shouldn't and there is a high + voltage on the control grid of the IF amp.
The problem ended up being a low resistance path across T-10 the 1st IF transformer. From pri to sec was about 1.5K this applied + 200vdc to the control grid 1st IF amp tube V-2. It didn't like that! Caused the tube to draw excessive plate current pulling the HV down.
I'm thinking that the two fixed caps in the IF can are shorted from silver migration, but that is yet to be seen. We do know that the IF transformer has resistance from pri to sec which it shouldn't and there is a high + voltage on the control grid of the IF amp.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
