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I got it. It wasn't a problem in the contrast pot or in any pot for that matter. A 270pf mica cap in the video IF was noisy. I remember Paul Carlson doing a restoration on a very high end RCA receiver that was incredibly sensitive and he traced a noise issue to a couple of mica caps that tested fine but when he put his self-made "Super Probe" on it, you could hear the noise in the cap very clearly. Same thing with the issue I had. The twitchy picture was being caused by one of these capacitors. Paul said restorers are going to have to start paying closer attention to 80 year old mica caps. The lower quality ones are now starting to break down and cause issues. Seems like he was right, at least in this TV.
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