Mind boggling screen issue

So here's the story, I replaced a screen with an aftermarket screen on IOS 10, screen worked fine, but the proximity sensor had come away from the camera flex so wasn't working, took it apart to try and reseat the proximity sensor, it still wouldn't work, whilst reconnecting had forgotten battery was still attached and blew the backlight filter, sent it away for repair, came back everything working but the home button, turns out the main home button flex on the screen had become faulty, in the mean time I had updated the IOS to 11.*.* and purchased a new screen, new screen wouldn't work, purchased several more screens and still won't work, I have bought 2 Genuine Apple screens and they won't work either, I have restored with DFU using non-gen and gen screens, now the strange thing is I still have the screen that was on when I blew the backlight filter and that works fine, and I have another screen with slight fault and that works fine, this morning I decided to try the gen Apple screen again and it fired up!! But only for about a minute, it was showing lines then the normal screen then it was fading then showing normal screen then it went off (black screen) and hasnt come back on again since? Any ideas please???