We see plenty of duff screens,its worth pressing along the top edge of the screen on the right hand side,you can in most cases replicate the fault and even cure it if you press hard enough,what happens is the micro connecters lift of due to heat,these cant be put back on ,but sometimes you can pack some rubber strips between the screen and the metal frame this applies enough pressure just to keep it working,its one hell of a bodge but seems to cure some of them.