Description: Broken fixing heater wire • It takes 15 s or more for the fixing temperature to reach 50°C/122°F after the power is turned on or the safety switch is turned off and on.• It takes 10 s or more for the fixing temperature to reach 100°C/212°F from 50°C/122°F. • It takes 24 s or more for the fixing temperature to reach the secondary stabilization fixing temperature from the primary stabilization fixing temperature. • It takes 15 s or more for the fixing temperature to reach 50°C/122°F after the power is turned on or the safety switch is turned off and on. • It takes 10 s or more for the fixing temperature to reach 100°C/212°F from 50°C/122°F. • It takes 24 s or more for the fixing temperature to reach the secondary stabilization fixing temperature from the primary stabilization fixing temperature.
Causes: Fixing heater installed incorrectly. Broken fixing heater wire. Poor contact in the fixing unit thermistor connector terminals. Broken fixing unit thermistor wire. Fixing unit thermistor installed incorrectly. Fixing unit thermostat triggered.
Remedy: Check and reinstall if necessary. Check for continuity. If none, replace fixing heater. Check the connection of connector CN11 on the main PCB and the continuity across the connector terminals. Remedy 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.
Code: C620
Description: Abnormally low fixing unit thermistor temperature • The fixing temperature remains below 90°C/194°F for 10 s during copying.
Causes: Fixing heater installed incorrectly. Broken fixing heater wire. Poor contact in the fixing unit thermistor connector terminals. Broken fixing unit thermistor wire. Fixing unit thermistor installed incorrectly. Fixing unit thermostat triggered.
Remedy: Check and reinstall if necessary. Check for continuity. If none, replace fixing heater. Check the connection of connector CN11 on the main PCB and the continuity across the connector terminals. Remedy 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.
Code: C630
Description: Abnormally high fixing unit thermistor temperature • The fixing temperature exceeds 230°C/446°F for 10 s.
Causes: 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.