Description: Fuser heater break The temperature does not reach 70 °C/ 158°F in 15 s before secondary stabilization. Temperature rise of 1°C/1.8°F does not occur in 5 s before secondary stabilization (except during printing).
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. 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: C6020
Description: Abnormally high fuser thermistor temperature Fuser thermistor is detected 230°C/ 446°F or more for 40 ms.
Causes: Shorted thermistor. Broken heater control circuit on the power source PWB
Remedy: Shorted thermistor. Measure the resistance. If it is 0Ω, replace the thermistor. Broken heater control circuit on the power source PWB. Replace the power source PWB and check for correct operation.
Code: C6050
Description: Abnormally low fuser thermistor temperature Fuser thermistor remains below 90°C/ 194°F for 1 s.
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 main/ 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 main/ engine PWB. Replace the main/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.