Back with a 630-TS Problem

[Yamamaya42]

There's an EXACT adjustment for the adjustment for the horz osc, in the SAMS, was that followed?

[DavGoodlin]

I have a similar issue with a 630 TS horizontal sync pulse getting lost before going to the oscillator.
Been sitting for months waiting for a fix after complete recap.
I'm working on it for another VK member who has a Philco 65 roundie for me as compensation.

First step is to check your work, one cap off by factor of 10 or to wrong spot can cause mayhem and we all have done it.

Synchro-guide is explained in RCA literature (can supply some if needed) and re-reading it may help both of us.

I'm enlightened by Wayne's last comment above; grounding a feedback loop can give a clue if oscillator itself has good output waveshape, part of adjustment procedure noted. (have a scope?) This may help uncover source of unstable operation.

[Chris K]

Originally Posted by DavGoodlin

I have a similar issue with a 630 TS horizontal sync pulse getting lost before going to the oscillator.
Been sitting for months waiting for a fix after complete recap.
I'm working on it for another VK member who has a Philco 65 roundie for me as compensation.

First step is to check your work, one cap off by factor of 10 or to wrong spot can cause mayhem and we all have done it.

Synchro-guide is explained in RCA literature (can supply some if needed) and re-reading it may help both of us.

I'm enlightened by Wayne's last comment above; grounding a feedback loop can give a clue if oscillator itself has good output waveshape, part of adjustment procedure noted. (have a scope?) This may help uncover source of unstable operation.

I have checked my work but in a comprehensive solder check, I can confirm the values once again. I have the RCA service guide for this TV but I don't think it describes the Synchro-guide operation. It would be awesome if you shared it!

I have 4 scopes so I think we will be OK! I've tried 4 different oscillator tubes in this including ones that work in other TVs.

The socket for the sync discriminator (V123), the 6AL5 needed to be replaced. I've checked the work multiple times but I'll do it again.

[Chris K]

Here is the circuit. Could the 6AC7 and associated components possibly be the problem? Ive switched it out with 2 different tubes and I pretty sure the pins are tight in the socket.

[Chris K]

Originally Posted by Yamamaya42

There's an EXACT adjustment for the adjustment for the horz osc, in the SAMS, was that followed?

Yes I followed that procedure. The issue is the jumping and not the frequency. As far as any of the instructions saying "pull in the picture untill..." that's not possible. The trace is a 15.75 khz sawtooth for a half second and then nonsense then back to a sawtooth then....

I wish there was a way to post video on VK. It would clearly demonstrate the fault.