RCA CTC 120, weird tuner issue

[vol.2]

Originally Posted by MRX37

Some help on what to try next would be appreciated. I can post video of how the set is acting if it will help.

Zeno is much better tech than I, but it looks like horizontal sync problems to me. Either caused by the tuner being dirty or something else. I remember seeing that kind of symptom and getting rid of it by grinding the tuning knob back and forth a bunch with deoxit in there.

I'm assuming you tried that and it didn't help though.

I guess the next step if no one else has any "known faults" to try, and you poked around for anything obvious already (caps with guts spewed or burnt spots on the PCB or reflowed solder), then the next step is to start checking voltages and hope you find a problem that way.

Problem is that I don't know that a sync problem would always manifest as a voltage issue. It's possible that something is just out of alignment. You never know if someone else got there first and started tweaking stuff. To do an IF alignment, I think you probably need a signal generator that can do a carrier wave or whathaveyou. I have never been able to do that because I lack that equipment. Perhaps there is some way to fake it with a normal signal generator, but idk.

If you have the schematics, you can at least check the main power supplies just to do a sanity check. I've caught a lot of BS that way. Otherwise if you don't have the schematic (better yet the SM), not sure how you'd do anything else beyond poking around.