Hard drive pin that needed to return to home position for the machine to boot would stick. A small drop would allow the spring to push it back home, and the drive would return to function.

I don’t remember all the details, but that’s the gist of it, yes.

A common problem with 80’s computer designs was socket creep - thermal expansions and contractions would cause chips and cards to gradually climb out of their sockets and slots over time, and this was very prevalent on one of the macs of ye olden days.

The official response when asked about this issue was to lift the computer a few cm off the desk and drop it back down to let everything reseat properly.

EDIT: Thanks to @fury@lemmy.world for providing additional info. See his response for more detail