• Code: C4200
• Description: BD steady-state problem
  • The VTC detects a BD error for 600 ms after the polygon motor rotation has been stabilized.
• Causes: Defective laser diode. Defective polygon motor. Defective main PCB.
• Remedy: Replace the LSU. Replace the LSU. Replace the main PCB and check for correct operation.

• Code: C5300
• Description: Broken cleaning lamp wire While the cleaning lamp is on, the broken cleaning lamp wire detection signal is detected for 2 s continuously.
• Causes: Defective cleaning lamp. Defective main PCB.
• Remedy: Replace the cleaning lamp. Replace the main PCB and check for correct operation.

• Code: C6000
• Description: Broken fixing heater wire
  • After secondary stabilization, detected temperature of the fixing thermistor is lower than 100 C/212 F
  • When the fixing heater is turned on, the output voltage of terminal CN2-1 of the power supply PCB is lower than 0.2 V.
  • 7 s after the fixing heater is turned on, the output voltage of terminal CN2-1 of the power supply PCB is lower than 0.2 V.
  • When the output voltage of terminal CN 2-1 of the power supply PCB is checked every 45 s during continuous copying, the voltage becomes lower than 0.2 V.
  • When the fixing temperature becomes lower than 140 C/284 F during copying, the output voltage of terminal CN 2-1 of the power supply PCB is checked and the voltage is lower than 0.2 V.
• Causes: Poor contact in the fixing unit thermistor connector terminals. Fixing unit thermistor installed incorrectly. Fixing unit thermostat triggered. Fixing unit heater M or S installed incorrectly. Broken fixing unit heater M or S wire.
• Remedy: Check the connection of connector CN10 on the main PCB and the continuity across the connector terminals. Repair or replace if necessary. Check and reinstall if necessary. Check for continuity. If none, replace the fixing unit thermostat. Check and reinstall if necessary. Check for continuity. If none, replace the fixing unit heater M or S.

• Code: C6020
• Description: Abnormally high fixing unit thermistor temperature
  • The fixing thermistor detects temperature 240 C/464 F or higher.
• Causes: Shorted fixing unit thermistor. Broken fixing unit heater control circuit on the power source PCB.
• Remedy: Measure the resistance. If it is 0 Ω, replace the fixing unit thermistor. Replace the power source PCB.

• Code: C6050
• Description: Abnormally low fixing unit thermistor temperature
  • The fixing thermistor detects temperature lower than 100 °C/212 °F for 10 s.
  • When fixing heater M is on, the temperature of the fixing thermistor is lower than 40 °C/104 °F and continues to drop for 24 s. (If the temperature in the copier is 10 °C/50 °F or less when power is turned on.)
  • When fixing heater M is on, the temperature of the fixing thermistor is lower than 40 °C/104 °F and continues to drop for 14 s. (If the temperature in the copier is higher than 10 °C/ 50 °F when power is turned on.)
• Causes: Poor contact in the fixing unit thermistor connector terminals. Broken fixing unit thermistor wire. Fixing unit thermistor installed incorrectly. Fixing unit thermostat triggered. Fixing unit heater M or S installed incorrectly. Broken fixing unit heater M or S wire.
• Remedy: Check the connection of connector CN10 on the main PCB and the continuity across the connector terminals. Repair or replace if necessary. Measure the resistance. If it is ∞Ω, replace the fixing unit thermistor. Check and reinstall if necessary. Check for continuity. If none, replace the fixing unit thermostat. Check and reinstall if necessary. Check for continuity. If none, replace the fixing unit heater M or S.

• Code: C6410
• Description: Fixing unit connector insertion problem
  • Absence of the fixing unit is detected continuously for 1500 ms while there is no error on the copier.
• Causes: Fixing unit connector inserted incorrectly. Defective fixing unit connector.
• Remedy: Reinsert the fixing unit connector if necessary. Replace the fixing unit.

• Code: C6420
• Description: Broken fixing unit thermistor wire
  • The fixing temperature remains at 0 C/32 F for 30 s continuously when the fixing heater is on.
• Causes: Poor contact in the fixing unit thermistor connector terminals. Broken fixing unit thermistor wire.
• Remedy: Check the connection of connector CN10 on the main PCB and the continuity across the connector terminals. Repair or replace if necessary.

• Code: C7300
• Description: Toner sensor problem
  • While the toner container sensor is on, the toner sensor in the developing unit does not turn on after the toner sensor turns off and toner is replenished from the toner container.
• Causes: Defective toner sensor. Poor contact in the toner sensor connector terminals. Defective toner container sensor. Defective toner container.
• Remedy: Replace the toner sensor. Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable. Replace the toner container sensor. Replace the toner container.