Quote:
Originally Posted by old_tv_nut
The question was, is the sound good at any contrast setting, even so low that the picture disappears. If both sound and picture fail at low setting, then that is just too low a signal. But if the sound is good (buzz gone) when the contrast is very low, that could be an indication of an intermodulation problem in the common stages that carry both.
Are you able to test the video IF tubes or substitute good ones? What I was guessing at is: maybe one of the IF tubes is bad, causing the contrast to be set to increase the gain in the others to the point where that first one that carries both sound and video is overloaded.
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I just tried it, and the buzz is steady as long as the picture is there, but fades away together with the picture as I continue to reduce the contrast.
I have a tube tester and I can certainly re-test the video IF tubes. I'll give that a try.
Thanks!