Zenith help please!

[dieseljeep]

Originally Posted by zeno

If the tubes are not lighting look to the primary being open.
AS A RULE you have a 2 green secondary for filaments 6.3 VAC
2 Yellow for the rectifier filaments only. 5 VAC
2 red & a red / yellow center tap to ground.
2 black primary.

2 reds go to rectifies plates.
Rectifier cathodes go to 1st filter cap. Then the B+ goes through the choke
thats in the speaker. Then another cap. This is the B+ for the outputs.
Runs 300- 400VDC
Other B+ sources are dropped by resistors & filtered.

73 Zeno
LFOD !

If you follow the schematic on N/A, you'll notice a rather strange approach to the fixed bias circuit. The speaker field circuit, plus the voltage divider circuit is in the negative source.
There is a strong possibility that one of the electrolytics was installed reverse polarity.
I have a radio like it in my collection that I bought from a fellow collector and it didn't seem to work very well. I checked to connections to the 'lytics in the p
ower supply, only to find that one went to chassis ground instead to the B- line. It happens!
I haven't played that radio in twenty years!