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The more I look at the pix off these Philcos, the more I think this is a chroma problem, not luma. A long-term ring like this has to come from some narrowband or sharp cutoff circuit. Suspects could be the IF or chroma, but I'm thinking maybe a sound trap - either misadjusted, or a poor design that bites into the upper chroma sidebands.
So - you might look at the sound trap or traps (there should be at least one) and check components and adjustment in that area.
>>Do you have a DVD with color bars? I'm thinking this might show clearly on some of the color bar edges if it's in the chroma.
Also, I recall some sets had a color take-off adjustment that was supposed to have a bandpass tilt opposite to the roll-off of the IF and sound trap. It would affect discoloration on edges, which shows in some of these pix, but I don't think it would cause that very long-term ringing. I think this adjustment was only in later Zeniths, but I thought I should mention it.
>>Can you post or link to the schematic of the last IF stage and all of the color take-off and chroma?
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