Top Screen not working

So I while ago my 3ds got bent on the hinge and the top Screen stopped working. About 2 weeks ago I took it apart to see what was wrong with it and it turns out the top screen worked fine but one of the cables was disconnected. I connected everything back and it worked fine and all I needed to do was get a new shell. At some point while the 3ds was apart the bottom screen stopped working and the top screen was ok. I tried everything to make it work and then the 3ds turned on but made a popping noise and turned. I figured that one out and I disassembled the top lcd. The bottom screen worked again but the top screen was just black. I tried everything and nothing worked. At that point I bought a broken 3ds to replace the too lcd. The 3ds arrived and both screens worked. I replaced the LCDs and the top screen wouldn't turn on. Does anyone know how I can fix it or is it just done?