Well, I replaced all the caps and the bottom of the horiz has started to collapse again. I can't get the HV over 22KV. The Flyback still looks good and resistance is in spec. I looked at the VDR, and it's already been replaced at least once, some other tech tacked a pink and white Zenith replacement VDR onto the leads of the original. I ordered one of the replacement Speer MOV's that Doug recommended in another thread. It should be here today. I'll let you all know the results once I solder it in. It would be hilarious if the caps were either fine or marginal and the VDR was the real culprit. If that's the case, I guess that'll teach me not to trust a $30 Chinese ESR cap tester.

I soldered in the new VDR. HV control is back, but the picture is still shrunken horizontally on the bottom third of the screen. It gets worse as the set warms up. I know for a fact that the Yoke is not the issue, as this is a NOS Thordarsen replacement. Once the set warms up, the bottom corners of the CRT shrink to black and the picture almost looks like a trapezoid. There are three white vertical lines centered in the bottom of the screen that fade out about a third of the screen up. Where the ticker on a cable news station would go, as an example, the text passes these lines, it shrinks and expands back to a normal size as it passes the vert. lines.

I really need help with this. I'm stumped.

a pic would be helpful

fyi, part of the pincushion correction in a zenith uses a pulse from the vert to modulate the output from the horz out tube. If you look a the circuit you can see a connection to I think a 40 uf cap (C7) that ties the screen of the horz out to the vert out.

This presents as a subtle narrowing and slight keystone of the pic (much less keystone than a bad yoke).

Sounds like the yoke....... yah, I know it's a new one.... you still got the original....?

We need a picture, several... when it's first on, and after a while...

.

its the after a while bit that makes me think its the pin cushion correction cap, if its just a 1/2 inch narrowing from top to bottom or bottom to top, then I would put money on that cap being an issue. Its even mentioned in the zenith tab manual case history as something that is often thought to be a yoke issue. Its just a lot less.

found it, knew I had messed with this before

http://www.videokarma.org/showpost.p...2&postcount=39

the full description stars on post 33

That entire thread was pretty good...... Boy you talk to yerself a lot....

.

I do that a lot, where I live its the only way to have an intelligent discussion.

This is really late, but thanks, Dave. That fixed it.

Works for where I live too.........

.

Great, glad that did it. Odd kind of failure, too subtle to be the yoke.