- Paper feed assist fan /Fr1 (FM21)
- Printer control board (PRCB)
- Check the connector connection and the wiring between PRCB and the fan, and repair it if any abnormality.
- Rotate the fan or I/O by hand, and repair it if abnormality. (Wiring diagram: Main body (2/4): 18-A).
- Replace FM21
- Replace PRCB.
