My Sega Nomad LCD is burnt and I need to replace it but I'm not sure which LCD I should pick.
Also My SNES jr cart slot is starting to fail, I sometimes need to put a piece of cardboard in front of my carts so that it pushes the cart towards the back of the slot in order to make them work.
Also the RF shield on my X-eye was so rusted I threw it up, not knowing it probably helped jumping a contact somewhere the CD drive stopped working after that (I need to find what contacts I need to jump so I can fix it)
Other than that the only other problem I've ever had is pretty common, I had to replace the rubber band on my Twn Famicom's disk drive.