• Code: C5600
• Description: Drum surface potential problem 1 • Grid voltage at 4.5 V could not determine the potential. • 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 • Grid voltage at 0.3 V could not determine the potential. • 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 50 C/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. 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. Replace the fuser thermostat. 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.

• Code: C6020
• Description: Fuser thermistor high-temperature detection error • The fuser temperature exceeds 235C/455F for 10 s. • The fuser high-temperature signal is detected for continous 500 ms.
• Causes: Installation defectiveness on fuser thermistor M and S. Defective fuser thermistor M and S. Defective engine 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 thermistor M and S. Replace the fuser thermistor M and S. Defective engine PWB. Replace the engine PWB.

• Code: C6030
• Description: Fuser thermistor break error • The fuser temperature remains at lower then 1 C/33.8F for 30 s continuously when the fuser heater is on.
• Causes: Defective engine PWB. Defective AC power source PWB. Installation defectiveness on fuser thermistor M and S.
• Remedy: Defective engine PWB. Replace the engine PWB. Defective AC power source PWB. Replace the AC power source PWB. 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.

• Code: C6050
• Description: Fuser thermistor abnormal temperature detection • During copying, the temperature at the heat roller lower than 120C/248F is detected continuously for 5 s.
• Causes: Installation defectiveness on fuser thermistor M and S. Operation on fuser thermostat. 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. Operation on fuser thermostat. Check for continuity. If none, replace the fuser thermostat. 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.

• Code: C6400
• Description: Zero-cross signal error • The engine PWB does not detect the zero-crossing signal (Z CROSS SIG) for 5 s.
• Causes: Poor contact in the connector terminals. Defective DC power source PWB. Defective engine PWB.
• Remedy: Poor contact in the connector terminals. Check the connection of connector YC11 on the engine PWB and YC6 on the DC power source PWB, and the continuity across the connector terminals. Repair or replace if necessary. Defective DC power source PWB. Check if the zero-crossing signal is output from YC6-3 on the DC power source PWB. If not, replace the DC power source PCB. Defective engine PWB. Replace the engine PWB if C6400 is detected while YC6-3 on the DC power source PWB outputs the zero-crossing signal.

• Code: C7200
• Description: Broken internal thermistor wire • The thermistor output value is 4.5 V or more.
• Causes: Poor contact in the connector terminals. Defective developing humidity sensor.Defective engine PWB.
• Remedy: Poor contact in the connector terminals. Check the connection of connector YC23 on the engine PWB and the continuity across the connector terminals. Repair or replace if necessary. Defective developing humidity sensor. Replace the developing humidity sensor. Defective engine PWB. Replace the engine PWB.