Question Horizonal line flickering Lenovo Y50-70 on high brightness?

Aug 3, 2022
I have a problem with my Lenovo Y50–70.
A while ago this horizontal line appeared at the top of the display, a few centimeters from the edge. Initially it was just a white hotrizontal line, after a few weeks, suddenly, other continuous ones appeared and started flashing. From the lines down, all over the screen, when the brightness is high enough, the screen is unusable. As seen in the video, artifacts such as yellow dots appear, the screen keeps the previous images for seconds after closing, the refesh rate drops dramatically, the resolution seems to drop. Previously it did it only at maximum brightness, now it is practically usable only at minimum brightness. The problem also occurs in bios and on other OS (no driver problem) On external monitors the problem does not occur (no GPU problem) The laptop did not suffer any bumps. I tried to discharge the residual electric charge, but nothing. I changed the matrix cable (flat cable that connects the motherboard to the display, but nothing has changed) The problem persists for weeks, then suddenly I turn on the laptop and there is nothing, no horizontal line, no artifacts. It stays perfect for like a week, then suddenly reappears, first just a line and then like after a day all the other problems come back, so I assume it's not the display, otherwise it should always have problems.

Video proof: