• Code: C630
• Description: Abnormally high fixing unit thermistor temperature
  • The fixing temperature exceeds 240˚C/464˚F for 10 s.
• Causes: Fixing unit thermostat triggered. Shorted fixing unit thermistor. Broken fixing 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: C710
• Description: Toner sensor problem
  • The sensor output voltage is outside the range of 0.5 to 4.5 V during toner control.
  • The toner sensor control voltage cannot be set within the setting range when maintenance item U130 is run.
• Causes: Defective toner sensor. Poor contact of the toner sensor connector terminals. Developer problem.
• Remedy: Replace the toner sensor. Reinsert the connector. Also check for continuity within the connector cable. If none, repair or replace the cable. Replace the developer.

• Code: C730
• Description: Broken external temperature thermistor wire
  • The input voltage is above 4.5 V.
• Causes: Poor contact of the humidity sensor PCB connector terminals. Defective external temperature thermistor.
• Remedy: Reinsert the connector. Also check for continuity within the connector cable. If none, repair or replace the cable. Replace the humidity sensor PCB.

• Code: C731
• Description: Short-circuited external temperature thermistor • The input voltage is below 0.5 V.
• Causes: Poor contact of the humidity sensor PCB connector terminals. Defective external temperature thermistor.
• Remedy: Reinsert the connector. Also check for continuity within the connector cable. If none, repair or replace the cable. Replace the humidity sensor PCB.

• Code: C740
• Description: Image formation unit connector insertion problem
  • Absence of the image formation unit is detected continuously for 1500 ms while there is no error on the copier.
• Causes: Image formation unit connector inserted incorrectly. Defective image formation unit connector.
• Remedy: Reinsert the image formation unit connector if necessary. Replace the image formation unit.

• Code: C817
• Description: Finisher front side registration motor problem
• Causes: A problem is detected with the front side registration motor.
• Remedy: See the finisher service manual.

• Code: C818
• Description: Finisher rear side registration motor problem
• Causes: A problem is detected with the rear side registration motor.
• Remedy: See the finisher service manual.

• Code: C819
• Description: Finisher trailing edge registration motor problem
• Causes: A problem is detected with the trailing edge registration motor.
• Remedy: See the finisher service manual.