Display Covered in Horizontal Lines

Hello,

I was given the task of fixing a Thunderbolt display at my university. If I can fix it, I get to keep it, so I accepted the challenge. First impressions of this display weren't too bad. The issue that it has however, is that when plugged in, all over the screen is a bunch of horizontal lines. I was told before testing it that when it was last powered on, there were only sections of the display that had lines, but I'm not certain if that was describing the same defect I was seeing on the display.

Either way, everything else seemed to work perfectly fine, so today I partially disassembled everything to see if there was anything clearly wrong. I can't remember if someone has already tried working on this unit before, but it looked very tidy. Everything looks intact, and visually the power supply and logic board looked good.

So, I'm not so sure where to start, I just know my issue may lie in either the logic board or the panel itself. I'm inclined to say the panel is flaky given the other issues I've seen here.

If anyone has any insight as to what I should try to do to troubleshoot, it would be greatly appreciated!!