1950s or '60s vintage Zenith TVs, Need some info

[Kevin Kuehn]

Originally Posted by vortalexfan

This may sound weird but now suddenly I'm getting 210V before and after R56, and R56 is not getting hot to the touch, but I'm still getting the weird voltage readings after C50 though, and still getting low voltage readings at pins 5 and 6 of the 5AQ5 tube socket.

I removed the output transformer completely from the circuit and took voltage readings and I'm getting 0V now at pins 1 and 7 of the 5AQ5 tube socket and pin 2 around 5V on the cathode and and still getting 22V on pins 5 and 6 of the 5AQ5 tube socket.

The -22V figure came in because of the fact that for some reason or another when I take voltage measurements on anything after C50 all the voltages are negative unless I flip my probes so that I use my positive probe as the negative probe and the negative probe as my positive probe and then I get positive voltage readings, and my reference to ground is the chassis because that's what its supposed to be according to the schematic.

You really don't want to run the set with the output transformer removed other than to take quick measurements because the 5AQ5 screen grid(pin 6) is still getting B+ and it's not healthy for the tube without the plate also getting B+. I really can't follow what you mean when you say everything after C50 is negative? Exactly where are you measuring negative voltage in respect to B- ?

I'd like to suggest we focus only on this little section instead of jumping all over the map. C50 is only a audio coupling cap that passes audio from the detector stage to the volume control, so we're really not worried about anything other than this little portion of the schematic. Once we figure out what's ailing the audio output then we can move onto the bigger picture.