@nixCraft I had a job for a summer back in the day repairing disk drives, albeit 3 1/2”. I had to align the heads with a special, very expensive disk with an analogue signal on it. I’d see some sort of measurement on the screen of the test PC, and I’d have to twiddle a screw on the heads to align them.

That was just at the cusp of it still being worth doing manually, and not just replacing the drive.

I can still smell the PC peripheral dust, no other dust smells like that.