• Code: C3100
• Description: Scanner carriage problem • The home position is not correct when the power is turned on or copying the document placed on the contact glass.
• Causes: Poor contact of the connector terminals. Defective scanner home position sensor. Defective engine board (KP-5238) or scanner board (KP-5063). Defective scanner motor.
• Remedy: Check the connection of connectors YC10, 11 on the engine board (KP-5238) and the continuity across the connector terminals. Repair or replace if necessary. Replace the scanner home position sensor. Replace the engine board (KP-5238) or scanner board (KP-5063) and check for correct operation. Replace the scanner motor.

• Code: C3200
• Description: Exposure lamp problem • In indicator check before starting copying, the average value in scanning of the shading plate with the CCD is 128 or more.
• Causes: Defective scanner board (KP-5063). Defective exposure lamp or inverter board. Incorrect shading position. Poor contact of the connector terminals.
• Remedy: Replace the scanner board (KP-5063) and check for correct operation. Replace the exposure lamp or inverter board. Adjust the position of the contact glass (shading plate). If the problem still occurs, replace the scanner home position sensor. Check the connection of connector YC7 on the scanner board (KP-5063), and the continuity across the connector terminals. Repair or replace if necessary.

• Code: C4000
• Description: Polygon motor synchronization problem • The polygon motor does not reach the stable speed within 15 s of the START signal turning on.
• Causes: Poor contact in the polygon motor connector terminals. Defective polygon motor. Defective engine board (KP-5238).
• Remedy: Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable. Replace the LSU. Replace the engine board (KP-5238) and check for correct operation.

• Code: C4010
• Description: Polygon motor steady-state problem • The polygon motor rotation is not stable for 5 s after the polygon motor rotation has been stabilized.
• Causes: Poor contact in the polygon motor connector terminals. Defective polygon motor. Defective engine board (KP-5238).
• Remedy: Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable. Replace the LSU.

• Code: C6000
• Description: Broken fixing heater wire • In fixing warm-up, the time to reach 50°C/122 °F exceeds 13.5 s, the time to reach 100°C/212 °F exceeds 10 s, the time to reach the primary stabilization exceeds 10 s or the time to reach the secondary stabilization exceeds 24 s.
• Causes: Poor contact in the thermistor connector terminals. Thermistor installed incorrectly. Thermal cutout triggered. Heater lamp installed incorrectly. Broken heater lamp wire.
• Remedy: Check the connection of connector YC4 on the power supply board and the continuity across the connector terminals. Repair or replace if necessary. Check and reinstall if necessary. Check for continuity. If none, replace the thermal cutout. Check and reinstall if necessary. Check for continuity. If none, replace the heater lamp.

• Code: C6020
• Description: Abnormally high fixing unit thermistor temperature • The fixing temperature exceeds 230°C/446 °F for 40 ms.
• Causes: Shorted thermistor. Broken heater control circuit on the power supply board.
• Remedy: Measure the resistance. If it is 0 Ohm, replace the thermistor. Replace the power supply board and check for correct operation

• Code: C6050
• Description: Abnormally low fixing unit thermistor temperature • The fixing temperature remains below 90°C/194°F for 1 s.
• Causes: Poor contact in the thermistor connector terminals. Broken thermistor wire. Thermistor installed incorrectly. Thermal cutout triggered. Heater lamp installed incorrectly. Broken heater lamp wire.
• Remedy: Check the connection of connector YC4 on the power supply board and the continuity across the connector terminals. Repair or replace if necessary. Measure the resistance. If it is infinity, replace the thermistor. Check and reinstall if necessary. Check for continuity. If none, replace the thermal cutout. Check and reinstall if necessary. Check for continuity. If none, replace the heater lamp.

• Code: C6400
• Description: Zero-crossing signal problem • The engine board (KP-5238) does not detect the zero-crossing signal for the time specified below. At power-on: 3 s Others: 5 s
• Causes: Poor contact in the connector terminals. Defective power supply board. Defective engine board (KP-5238).
• Remedy: Check the connection of connectors YC7 on the engine board (KP-5238) and YC2 on the power supply board, and the continuity across the connector terminals. Repair or replace if necessary. Check if the zero-crossing signal is output from YC2-11 on the power supply board. If not, replace the power supply board. Replace the engine board (KP-5238) if C6400 is detected while YC2-11 on the power supply board outputs the zerocrossing signal.