Entertainment Center: TVs, Stereos, VCRs and DVDs - JVC tv, picture shrinks to horizontal band

I have a JVC tv, model C-2018. When it is on, there is a small bright line about 1" from the bottom. Then after it has been on for just a few minutes, the bottom becomes unstable, as if the bottom 40 lines get compressed into about 5. Then suddenly the whole picture becomes a jumbled band about 1" high in the center of the screen.

I removed the back and sprayed a lot of dust with compressed air, but the problem is still there. I suspect it has to do with heat.

Any hints on how to troubleshoot this particular problem? Thanks.

JVC is notorious for having hot vertical IC's.
You probably have a bad connection on the circuit board that needs resoldering.

There are a couple hundred solder joints on both the top and bottom of the circuit board. Any tips on how to figure out which ones are bad?

if you look on the pc board you should find transistors mounted to metal heatsinks. look on the board some are labelled vertical horizontal etc. try soldering the vertical drive and vertical output transistors as well as any electrolytic capacitors. capacitors are also a common problem in the vertical section.

hope this helps

kurt