• Code: C6050
• Description: Abnormally low fuser thermistor temperature
  Fuser thermistor remains below 90°C/ 194°F for 1 s.
• Causes: Poor contact in the fuser thermistor connector terminals.
  Broken fuser thermistor wire.
  Fuser thermistor installed incorrectly.
  Fuser thermostat triggered.
  Fuser heater installed incorrectly.
  Broken fuser heater wire.
• Remedy: Poor contact in the fuser thermistor connector terminals. Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable.
  Broken fuser thermistor wire. Measure the resistance. If it is ∞, replace the fixing thermistor.
  Fuser thermistor installed incorrectly. Check and reinstall if necessary.
  Fuser thermostat triggered. Check for continuity. If none, replace the fuser thermostat.
  Fuser heater installed incorrectly. Check and reinstall if necessary.
  Broken fuser heater wire. Check for continuity. If none, replace the fuser heater.

• Code: C6400
• Description: Zero-cross signal error
  Interrupt of the zero-cross signal does not occur more than 1 s.
• Causes: Poor contact in the connector terminals.
  Defective power source PWB.
  Defective engine PWB
• Remedy: Poor contact in the connector terminals. Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable.
  Defective power source PWB. Check if the zero-crossing signal is output from YC2-2 on the power source PWB. If not, replace the power source PWB.
  Defective engine PWB. Replace the engine PWB if C6400 is detected while YC2-2 on the power source PWB outputs the zero-crossing signal.

• Code: C7800
• Description: Broken external thermistor wire
  The thermistor output value is 0.5 V or less.
• Causes: Poor contact in the connector terminals.
  Defective humidity sensor.
• Remedy: Poor contact in the connector terminals. Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable.
  Defective humidity sensor. Replace the cassette PWB and check for correct operation.

• Code: C7810
• Description: Short-circuited external thermistor wire
  The thermistor output value is 4.5 V or more.
• Causes: Poor contact in the connector terminals.
  Defective humidity sensor
• Remedy: Poor contact in the connector terminals. Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable.
  Defective humidity sensor. Replace the cassette PWB and check for correct operation.

• Code: C8170
• Description: Built-in finisher front side registration motor problem
  When the front-side registration home-position sensor is turned on during initialization, the sensor did not turn on while it has moved by 106 pulses. When the front-side registration home-position sensor is turned off during initialization, the sensor did not turn on in 3 s.
• Causes: The front side registration motor connector makes poor contact.
  Defective front side registration motor.
  The front side registration home position sensor connector makes poor contact.
  Defective front side registration home position sensor.
  Defective finisher control PWB.
• Remedy: The front side registration motor connector makes poor contact. Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable.
  Defective front side registration motor. Replace front side registration motor.
  The front side registration home position sensor connector makes poor contact. Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable.
  Defective front side registration home position sensor. Replace the front side registration home position sensor.
  Defective finisher control PWB. Replace the finisher control PWB and check for correct operation.

• Code: C8180
• Description: Built-in finisher rear side registration motor problem
  When the rear-side registration home-position sensor is turned on during initialization, the sensor did not turn on while it has moved by 106 pulses.
  When the rear-side registration home-position sensor is turned off during initialization, the sensor did not turn on in 3 s.
• Causes: The rear side registration motor connector makes poor contact.
  Defective rear side registration motor.
  The rear side registration home position sensor connector makes poor contact.
  Defective rear side registration home position sensor.
  Defective finisher control PWB.
• Remedy: The rear side registration motor connector makes poor contact. Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable.
  Defective rear side registration motor. Replace rear side registration motor.
  The rear side registration home position sensor connector makes poor contact. Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable.
  Defective rear side registration home position sensor. Replace the rear side registration home position sensor.
  Defective finisher control PWB. Replace the finisher control PWB and check for correct operation.

• Code: C8190
• Description: Built-in finisher trailing edge registration motor problem
  When the trailing edge registration home-position sensor is turned on during initialization, the sensor did not turn on while it has moved by 106 pulses.
  When the trailing edge registration home-position sensor is turned off during initialization, the sensor did not turn on in 3 s.
• Causes: The trailing edge registration motor connector makes poor contact.
  Defective trailing edge registration motor.
  The trailing edge registration home position sensor connector makes poor contact.
  Defective trailing edge registration home position sensor.
  Defective finisher control PWB.
• Remedy: The trailing edge registration motor connector makes poor contact. Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable.
  Defective trailing edge registration motor. Replace trailing edge registration motor.
  The trailing edge registration home position sensor connector makes poor contact. Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable.
  Defective trailing edge registration home position sensor. Replace the trailing edge registration home position sensor.
  Defective finisher control PWB. Replace the finisher control PWB and check for correct operation.

• Code: C8210
• Description: Built-in finisher stapler problem
  The stapler home position sensor does not change state from nondetection to detection within 200 ms of the start of stapler motor counterclockwise (forward) rotation. During initialization, the stapler home position sensor does not change state from non-detection to detection within 600 ms of the start of stapler motor clockwise (reverse) rotation.
• Causes: The stapler connector makes poor contact.
  The stapler is blocked with a staple.
  The stapler is broken.
  Defective finisher control PWB.
• Remedy: The stapler connector makes poor contact. Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable.
  The stapler is blocked with a staple. Remove the stapler cartridge, and check the cartridge and the stapling section of the stapler.
  The stapler is broken. Replace the front stapler and check for correct operation.
  Defective finisher control PWB. Replace the finisher control PWB and check for correct operation.