In this episode I fix the drive mechanism from the Commodore 2031 disk drive which was suffering from a 1541 identity crisis. This involved rewinding the spindle motor tachometer, replacing the (replacement!) spindle motor drive belt, and fixing egregious alignment issues due to a dodgy track 0 stop.

I previously diagnosed the tachometer issue in episode 3 of floppies rock: https://www.youtube.com/watch?v=hD0U8kDFsvc

Timestamps
00:00 Intro
00:33 Recap of drive mechanism issues
02:36 Motor tachometer theory
03:40 Measuring working tachometer
05:36 Closer look at faulty tachometer
11:58 Rewinding the faulty tachometer
21:05 Testing the rewound tachometer
26:49 Testing reassembled drive mechanism
30:11 Replacing the drive belt (again)
32:23 Alignment issues
35:49 Track 0 stop issues
40:24 Final testing
41:46 Wrap-up

The problems I hit and fixed in this episode:

  • The replacement drive belt I previously fitted (4mm x 91mm diameter) turned out to be too big. I ended up using 4mm x 88mm.
  • The stepper motor tachometer winding was broken. I rewound with 40AWG magnet wire.
  • The drive was way out of alignment as the track 0 stop had been replaced with a bent paperclip. I adjusted the bent paperclip and re-aligned. I may replace the bent paperclip with a better solution in future.

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