Either the GPU is failing, the ribbon cable connecting the panel to the controller board is failing (or loose), or the ribbon connecting the controller to the motherboard is loose. You should look up a teardown video of your laptop, and try reseating and and all ribbon cables but particularly the one travelling through the hinge.

had a similar issue where the backlighting for my screen would turn off randomly and come back on when i restarted. took it to an it guy and he said it was faulty power wiring that was screwing with it. advised me it was cheaper to get a new laptop than to fix the old one.

>>33510
That's what LCDs do when they were getting a signal but now aren't. First step is to split the laptop and dismantle the screen half, then put everything back together. If that doesn't sort it, you need a new ribbon cable.

Google "<your laptop> service manual", then follow the instructions for replacing the LCD panel. If you need a ribbon cable, hit up eBay. Make sure you get the right cable for the exact panel you're using. Photograph the cable while it's out; that'll make your life easier if you need to buy a replacement.

>>33511
Then he's an idiot: all it needed was a teardown and a new ribbon cable.