Hey all... I've got an old (1996?) JVC AV-27BP6 27" television with a problem.

After it warms up for a minute or two, some horizontal black lines start to appear on the bottom of the screen. They flicker and scroll a bit, often reaching halfway up the screen and distorting the picture. There are anywhere from 5-25 lines, sort of a venetian blind effect. Hitting the side of the tv usually makes them go away for 5-10 minutes, but lo and behold they return!

I know that this is an oldish tv and is probably not worth doing any major repairs to, but I'm wondering if this is something that I could fix myself without being an expert (I do have some very rudimentary electronic repair skills). I'd like to avoid replacing the tv because besides those lines the picture is great, plus I'm on quite a tight budget these days and really only use it occasionally for movies. Because the hitting seems to work it makes me think there's a loose connection somewhere...

If anyone is familiar with this sort of problem and could point me in the right direction for a fix, I'd be *greatly* appreciative! Thanks...
-Rob