Brother HL-L5000D Service Manual page 69

 Error code 0300
Cannot detect the lock signal of the polygon motor for the laser unit (second time).
Error code 0305
Cannot detect the lock signal of the polygon motor for the laser unit (first time).
Error code 0401
Cannot detect the synchronized signal of the polygon motor for the laser unit (second time).
Error code 0405
Cannot detect the synchronized signal of the polygon motor for the laser unit (first time).
Step
Connection failure of the laser
1
unit flat cable
2 Laser unit flat cable failure
3 Laser unit failure
4 Main PCB failure
Cause
Reconnect the laser unit flat cable.
Replace the laser unit flat cable.
Replace the laser unit.
Replace the main PCB ASSY.
2-43
Remedy
Confidential