focus rectifier sub.

[ctc17]

Originally Posted by ctc17

I have some SI hv rectifiers out of microwave oven. On my list to try some day. milot porg boilet skoimler

Microwave ovens dont have rectifiers in them.

[dieseljeep]

Originally Posted by ctc17

Microwave ovens dont have rectifiers in them.

That statement might be a little wrong. I saw one diode connected from the cap to the chassis ground. I heard they have a voltage doubler circuit in them.

[dieseljeep]

Originally Posted by Don Lindsly

Check the focus control and divider resistors for burns and/or arcing. Do you have the chassis number?

I don't know if that was a problem with that model, but I had problems with corona arcing on later sets, like the 16Z8C50 and simular models. In a low light, high humidity condition, you could see corona arcing around the solder terminals of the focus components. I had to change the flyback to correct the problem.
As you can see, RCA only used that focus stick in the CTC15 chassis. The older and newer chassis went back to the tube focus rectifier.

[Electronic M]

Originally Posted by Gunslinger

don't forget to chaeck the crt socket. They were troublesome.

I have a 1971 Zenith hybrid that has had focus issues in the past(I just jurry rig mega-ohm resistors into the HV divider to bring it back to speck when it drifts) and lately the blue and red screen voltages will intermittently(reciently it is almost always bad) drop to the point of cutting off their guns and be unaffected by the controls. Could the CRT socket cause this? The socket does have spark gaps built in...

[Gunslinger]

Originally Posted by Electronic M

I have a 1971 Zenith hybrid that has had focus issues in the past(I just jurry rig mega-ohm resistors into the HV divider to bring it back to speck when it drifts) and lately the blue and red screen voltages will intermittently(reciently it is almost always bad) drop to the point of cutting off their guns and be unaffected by the controls. Could the CRT socket cause this? The socket does have spark gaps built in...

I used to disconnect the metal grounding strap. If the spark gaps were bad, the problem disappeared. This was for testing only. Do not leave the grounding strap disconnected.

[Electronic M]

Thanks for the advise! I'll try that.