Well, I broke my ps1 by physically disc swapping too much with a mod device to play booted games, but it still turns on fine, the laser is fine, everything "works" per se I just broke the part the disc snaps on to.
Also would have a working ps2 if not for disc swapping custom copies of guitar hero at a certain boot screen... Lent it to friends with the face plate off and they broke the machine.
The N64 we have laying around still works... Sometimes. It randomly freezes and I think it has something to do with the component cables on the back. Sometimes it works fine though, things built like a tank