I had a similar issue on a TR1MP I got the other day, turned out to be the metal screen surround being loose. This is a thin shaped aluminium piece that clips over the glass of the screen inside and it is fixed with two screws to the LCD printed circuit board.
Both these screws had worked loose and because the surround is an earthing point, or shielding for the screen, just touching it lightly made the screen flicker in horizontal lines. I tightened the screws and it’s been fine since. They screw in from the rear of the LCD top corners through holes in the circuit board, so you’d not see them unless you take the screen out.
This might not be your problem, but worth checking out
Warning if you do this be very careful… the screen is made up of two mm thin pieces of glass with liquid crystal in between, and undue twisting or pressure in one point will crack it. They a very costly to replace even second-hand on eBay