I took the set apart and tried tapping different parts of the mainboard, subboards, and the chassis again. Nothing reproduced the lines, or even caused an effect.
On my old Panasonic with a cold joint in the vertical section, tapping the set, or even walking around it, would cause the picture to jump around and compress vertically. With the cold joint repaired it was rock solid.
Here are the symptoms:
1) Flickering horizontal lines that come and go, sometimes present for hours, sometimes missing.
2) The lines slowly scroll from bottom to top when they are there.
The following causes were suggested:
1) Bad power. I tried the Tripp Lite conditioner mentioned earlier in the thread without success. x
2) Cold solder joints. My understanding is that these are susceptible to physical trauma, which I have tested by tapping various parts of the set.
3) Bad filter capacitors. Is there a way to eliminate this as an option?
4) Perhaps the set always had these lines.
I would really like to get this set working 100% again.
Quote:
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Is it a single line, or a bunch of lines? A bunch of lines, each rapidly flickering on and disappearing while the whole bunch slowly scrolls is probably motor interference.
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Two or three lines slowly scrolling up. Sometimes they are more sudden and are just black horizontal flickers (like in the video from the first post).