Quote:
Originally Posted by dr.ido
When the lines at the top of the screen go away has the picture height increased (and pushed the lines outside of the visible area)?
Those lines look like Macrovision or some other data inserted in the vertical blanking period. If the you're signal source is a DVD player a copied DVD will not have the Macrovision protection on it. If you're signal source is a cable box it's more likely to be data rather than Macrovision protection - here the cable co only turned on Macrovision for PPV. Some channels did insert data (usually during commercials) that a couple of my sets had trouble with.
If the lines stay the same (at least for the first 2 minutes while they're there) with different signal sources marginal caps in the vertical section are certainly possible. I'd look at the small electrolytics (under 100uF) first. When I was doing a lot of these I could probably guess which pin of the vertical IC (at least for a few common types) it could be hanging off, but I doubt I remember it now.
I've experienced the buzzing (especially around text) with various sets, but I've never found a definite solution. I did find it didn't occur with over the air broadcasts (not that helps anymore) - only the output from other sources. My solution back in the day was to turn the TV volume down and run the audio from the VCR/etc through the stereo.
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No, the picture does not change size, it's widescreen all along, I will do some more testing and i'll get back to you on that one. As for the caps, that was my first assumption. That set is 35 years old, so at one point those caps are all going to go bad and create a lot of weird problems. As soon as I get an soldering iron I'll start changing them.
As for the buzzing, pretty much all my tv's do it, but this one is consistently louder than the others. It's weird, I can't imagine a tv going out of the production line like that...but as you said, in 79 most of the tv's source where from "air transmission" so maybe tvs where not designed with other sources in mind, and that might be the problem. Maybe a different RF modulator would do the trick...?