Disk drive head not moving
- If the stepper tries to move, but nothing happens, the mechanics are probably stuck because all lubricant dried up.
- If stepper does not move at all and this happens for both disk drives, the FDC (Floppy Disk Controller) chip (FD 1719) may be broken.
- Make sure all mechanic parts are well lubricated.
- Try swapping the drives by moving the jumpers from drive A to drive B. If the exact same thing happens with drive B, it's probably not a drive issue.
- Replace the FDC chip with a known working chip.