• Code: C4120
• Description: BD initialization (C) problem
  • When power is turned on, only laser C is output and ASIC of main PWB detects a BD error for 2000 ms.
• Causes: Defective laser scanner unit.
  Defective main PWB.
  Poor contact in connector terminals.
• Remedy: Defective laser scanner unit. Replace the laser scanner unit.
  Defective main PWB. Replace the main PWB and check for correct operation.
  Poor contact in connector terminals. Check the connection of connector YC8 on the main PWB and the continuity across the connector terminals. Repair or replace if necessary.

• Code: C4200
• Description: BD steady-state problem
  • ASIC of the main PWB detects a BD error A for 4000 ms after the polygon motor rotation has been stabilized.
• Causes: Defective laser diode.
  Defective polygon motor.
  Defective main PWB.
  Poor contact in connector terminals.
• Remedy: Defective laser diode. Replace the laser scanner unit.
  Defective polygon motor. Replace the laser scanner unit.
  Defective main PWB. Replace the main PWB and check for correct operation.
  Poor contact in connector terminals. Check the connection of connector YC8 on the main PWB and the continuity across the connector terminals. Repair or replace if necessary.

• Code: C5100
• Description: Main high-voltage error
  • While the main high-voltage output remote signal is on, an alarm signal is detected continuously for 400 ms.
• Causes: Defective high voltage PWB.
  Leak of main high-voltage.
  Poor contact in connector terminals.
• Remedy: Defective high voltage PWB. Replace the high voltage PWB and check for correct operation.
  Leak of main highvoltage. Check the main charger unit and replace if necessary.
  Poor contact in connector terminals. Check the connection of connector YC7 on the engine PWB and the continuity across the connector terminals. Repair or replace if necessary.

• Code: C5500
• Description: Drum surface potential sensor problem 1
  • The sensor output is 0.5 V or less when MC REM signal is turned on.
• Causes: Poor contact in the drum surface potential sensor connector terminals.
  Defective drum surface potential sensor.
  Defective high voltage PWB.
  Defective engine PWB.
• Remedy: Poor contact in the drum surface potential sensor connector terminals. Check the connection of connector YC5 on the engine PWB. Reinsert the connector. Also check for continuity within the connector cable. If none, repair or replace the cable.
  Defective drum surface potential sensor. Replace the drum surface potential sensor.
  Defective high voltage PWB. Replace the high voltage PWB and check for correct operation.
  Defective engine PWB. Replace the engine PWB and check for correct operation.

• Code: C5510
• Description: Drum surface potential sensor problem 2
  • The sensor output is 4.5 V or more when the MC REM signal is turned on.
• Causes: Defective drum surface potential sensor.
  Defective high voltage PWB.
  Poor contact in the drum surface potential sensor.
• Remedy: Defective drum surface potential sensor. Replace the drum surface potential sensor.
  Defective high voltage PWB. Replace the high voltage PWB and check for correct operation.
  Poor contact in the drum surface potential sensor. Check the connection of connector YC5 on the engine PWB. Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable.

• Code: C5600
• Description: Drum surface potential problem 1
  • The sensor output is 4.5 V or more.
  • Potential adjustment in 30 times could not raise the potential sensor value to the predetermined.
• Causes: Deteriorated main charger.
  Grid or main charger shield is dirty.
  Defective drum surface potential sensor.
  Defective high voltage PWB.
  Defective engine PWB.
• Remedy: Deteriorated main charger. Check the main charger wire and replace it if necessary.
  Grid or main charger shield is dirty. Clean the grid or main charger shield if necessary.
  Defective drum surface potential sensor. Replace the drum surface potential sensor.
  Defective high voltage PWB. Replace the high voltage PWB and check for correct operation.
  Defective engine PWB. Replace the engine PWB and check for correct operation.

• Code: C5610
• Description: Drum surface potential problem 2
  • The sensor output is 0.5 V or less.
  • Potential adjustment in 30 times could not lower the potential sensor value to the predetermined.
• Causes: Defective drum surface potential sensor.
  Defective high voltage PWB.
  Defective drum.
  Defective engine PWB.
• Remedy: Defective drum surface potential sensor. Replace the drum surface potential sensor.
  Defective high voltage PWB. Replace the high voltage PWB and check for correct operation.
  Defective drum. Replace the drum.
  Defective engine PWB. Replace the engine PWB.

• Code: C6000
• Description: Fuser heater lamp break
  • The fuser temperature does not increase for 40 s after the fuser heaters have been turned on for warming up.
  • The fuser temperature remains below 50C/122F for 10 s continuously after the fuser heaters have been turned on during stabilization.
• Causes: Installation defectiveness on fuser thermistor M and S.
  Defective fuser thermostat 1 or 2.
  Installation defectiveness on fuser heater L, M or S.
  Broken fuser heater L, M and S wire.
  Defective engine PWB
  Defective AC power source PWB.
• Remedy: Installation defectiveness on fuser thermistor M and S. Check the mounting state of the fuser thermistor M and S. If any problem is found, repair it.
  Defective fuser thermostat 1 or 2. Replace the fuser thermostat 1 or 2.
  Installation defectiveness on fuser heater L, M or S. Check the mounting state of the fuser thermistor L, M and S. If any problem is found, repair it.
  Broken fuser heater L, M and S wire. Check for continuity. If none, replace the fuser heater L, M and S.
  Defective engine PWB. Replace the engine PWB.
  Defective AC power source PWB. Replace the AC power source PWB.