Chosen Solution

My grandparents recently found an old NES and they decided to give it to me. However, both the door flap and the tray are very squeaky and I was wondering if there was a way to fix that. Everything on the NES works normally, but the squeaking kinda hurts my ears.

Hi! I think there is a way to fix this. Just follow this guide to remove the cartridge tray from the system. Then use some WD40 to lubricate the moving parts. Make sure you give it enough time to dry out a bit and wipe any excess fluid carefully with alcohol. Do the same thing to the hinge of the door flap, just be careful not to spill WD40 on the main board or on any other electrical parts. If you do, wipe it with alcohol as fast as possible.

Dont Worry, both of mine have that too. It wont affect your console at all.