Good luck with the rest, Dennis. A problem that others have not mentioned is a broken size detect sensor (ie a 1.4MB disk is identified as an 800KB disk).

Many years ago, a colleague gave me a 1.4MB auto-inject drive where the head assembly springs had been damaged. The owner had attempted to fix the problem by sticking a UK two pence coin onto the disk head to weight it down. I still own the drive for spares, but I have spent the two pence.