1968 Zenith 20Y1C50 chassis - advice needed

[joe111671]

Originally Posted by JohnCT

I don't know if you have a HV probe, but the easiest way to find this is to check the focus voltage at the flyback where the black lead attaches to the 4.7M resistor (should be 4-6KV or so). If it starts high when the TV is in focus and drops off when the pic gets blurry, pull the socket off the back of the tube and see if the voltage comes back up. If it does, there's either a problem inside the tube itself or the plastic pin guide may have carbon tracking on it or *under* it. If the voltage stays down with the socket removed, unsolder the black lead on the 4.7M resistor and see if the voltage stays up. If it does, the socket is bad.
John

I think I understand, and I do have a HV probe. Correct me if I got it wrong, but what I'm checking is the focus voltage to the CRT on the black wire. If it drops when the picture goes out of focus, it's either the CRT itself, or the socket, and I'm going to be finding whether it's one or the other by these tests.

But if it's the rectifier stick - will the voltage just come up to a certain point and stay there without dropping? That's the only thing I'm unsure of right now, could a bad rectifier stick produce the higher initial voltage and then drop?