The drive for our old C64 developed a thing fairly early on where some spring or other near the back would get out of alignment and the head would stop reading.

The drive for our old C64 developed a thing fairly early on where some spring or other near the back would get out of alignment and the head would stop reading. It basically just needed to be poked back into place with a fingertip, but you had to open up the casing to do it. After repeated repair requests from frantic seven-year-olds, Dad cut a hole in the back of the drive just big enough to poke the blunt end of a pencil through so we could fix it ourselves. I learned to detect the subtle change in the drive's whirr when it was out of alignment, to distinguish that from any of the other things that could go wrong (corrupt disks, usually).