LowB+ in a CBS Ch 817-6

[Doug66]

I've been working on and off with the set since April, giving up and coming back to it.

I started with no vertical, but a new transformer fixed that. Low B+ was next, about 100V too low.

The only thing that would bring the 340V back up was to disconnect it from pin 8 of the flyback, but that fried C3. I found a NOS new and used flyback as well as a yoke and bought all 3. I put in the yoke which made no difference. Trying the used flyback gave me no light on the screen, but the voltages were still too low.

I put the original flyback back in and this time I did con nect the 340 Volt and 330 volt yoke leads. That kept the voltage right. I connected the 340V lead and all was good. Connecting the other yoke lead to 330V caused it to drop.

Realizing the problem is in the 330V line, I disconnected everything going to it and isolated the problem. 330V goes the R99 then R98 onto pin 4 of the output tube 12BQ6. Disconnecting R98 from pin 4 brings the voltage back up. R98, R99 and C86 have been replaced, and I have tried another good 12BQ6.

I'm out of ideas.
Thanks