Code :

Code: C630
Description: Abnormally high fixing unit thermistor temperature • The fixing temperature exceeds 230C/446F for 10 s. • The fixing unit high temperature detection circuit on the engine PCB detects an abnormally high temperature.
Causes: Shorted fixing unit thermistor. Broken fixing unit heater control circuit on the power source PCB.
Remedy: Measure the resistance. If it is 0 , replace the fixing unit thermistor. Replace the power source PCB.

Code: C640
Description: Zero-crossing signal problem • The main PCB does not detect the zero-crossing signal (Z CROSS SIG) for the time specified below. At power-on: 3 s Others: 5 s
Causes: Poor contact in the connector terminals. Defective power source PCB. Defective main PCB.
Remedy: Check the connection of connectors CN5-5 on the main PCB and CN2-7 on the power source PCB, and the continuity across the connector terminals. Repair or replace if necessary. Check if the zero-crossing signal is output from CN2-7 on the power source PCB. If not, replace the power source PCB. Replace the main PCB if C640 is detected while CN2-7 on the power source PCB outputs the zero-crossing signal.

Code: C650
Description: Broken fixing unit thermistor wire The fixing temperature remains at 0C/ 32F 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 CN5-12 on the engine 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.

Code: C710
Description: Toner sensor problem • The sensor output voltage is outside the range of 0.5 to 4.5 V during copying or in maintenance item U130. • The toner sensor control voltage cannot be set within the range in maintenance item U130.
Causes: Defective toner sensor. Poor contact in 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, remedy or replace the cable. Replace the developer.

Code: C720
Description: Broken drum thermistor wire The drum thermistor input voltage is 4.5 V or more when the front cover is closed.
Causes: Broken druterminals.m thermistor wire. Poor contact in the drum thermistor connector
Remedy: Measure the resistance. If it is ∞Ω, replace the drum thermistor. Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable.

Code: C721
Description: Shorted drum thermistor The drum thermistor input voltage is 1.2 V or less when the front cover is closed.
Causes: Broken drum thermistor wire. Defective main PCB.
Remedy: Measure the resistance. If it is 0 , replace the drum thermistor. Replace the main PCB and check for correct operation.

Code: C722
Description: Broken drum heater wire The drum temperature does not change within 5 minutes of the drum heater turning on.
Causes: Broken drum heater wire. Poor contact in the drum heater connector terminals. Defective power source PCB.
Remedy: Check for continuity within the drum heater. If none, replace the drum heater. Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable. Check if the drum heater turns on when CN16-9 on the engine PCB goes low. If not, replace the power source PCB.

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