Television and Home Theater

I would like to repair my TV if possible. During the past year or so, the following symptoms occured:
1) green sceen (had to unplug to reset)
2) the picture image has been stretched vertically but would correct after 5 minutes.
3) symptom (2) would correct if I smacked the TV on the cabinet
Unfortunately the vertical is now distorted or rather flickers. It will not correct by smacking, just seem to flicker a bit more. When initially on, picture is OK but then begins to flicker (distorted) again and cannot correct. Sound is fine. Sometimes upper half of picture is fine.

I have a 41" sony module #KP41EXR96 that I'm working on and I have POOR CONVERGENCE. I've checked IC1705 "STK4278" both 100uf25V caps "C1715" and "C1745". They all test fine. Please can someone give me a proceadure and drawing of the convergence board.

Thanks,
Clayton

I own a Magnavox Widescreen HDTV model; 30MW5405. My problem is that whenever I watch a HD program, I get grey letterboxes. Instead of filling the widescreen, it stretches it and has the grey on top and bottom of the screen. It is very annoying. Is there a way of changing this? I don't enjoy my HDTV shows this way at. :(