Panasonic CT-36G22V gremlin I can't track down!

[MRX37]

Awhile back I sold a 36 inch Panasonic CT-36G22V to a close friend. When the TV left my house, it worked fine. when it got to his apartment, it developed some weird gremlin where even the slightest vibration, even gently tapping the TV will disturb the picture. The TV may also shut off by itself and needs to be whacked a few times before you can turn it back on. Also, sometimes the picture will collapse to a line across the middle of the screen. (no vertical)

Thinking there's a few bad solder connections inside the TV, I have so far resoldered the flyback, HOT, a couple other large transistors, and pretty much every connection in the power supply. I also scanned the board and touched up any solder connection that looked even slightly suspicious.

The board is free of any cracks or damage. This TV has a few cards plugged into the main board. I took out the card in the power supply section and touched up all the solder joints on it.

So far, the picture hasn't collapsed to a line yet, but it's been looking like it wants to, and even the slightest vibration will disturb the image. Also, I'm not certain but the image looks maybe a little too high, like the vertical height is a tad too high. I'm at a loss on where to narrow my focus to.