• Code: 6020
• Description: Abnormally high fuser unit thermistor temperature
  • The fuser temperature exceeds 230 °C/446 °F for 10 s.d on
• Causes: Shorted fuser unit thermistor. Broken fuser unit heater control circuit on the power supply unit.
• Remedy: Measure the resistance. If it is 0Ω, replace the fuser unit thermistor (see page 1-6-22). Replace the power supply unit.

• Code: 6050
• Description: Abnormally low fuser unit thermistor temperature
  • The fuser temperature remains below 120 °C/248 °F for 10 s. • When power is turned on, the fuser temperature does not reach 40 °C/ 104 °F even if 14 (FS-9100DN) or 20 (9500DN) seconds elapse.
• Causes: Poor contact in the fuser unit thermistor connector terminals. Broken fuser unit thermistor wire. Fuser unit thermistor installed incorrectly. Fuser unit thermostat triggered. Fuser unit heater M or S installed incorrectly. Broken fuser unit heater M or S wire.
• Remedy: Check the connection of connector CN10 on the engine controller PWB and the continuity across the connector terminals. Repair or replace if necessary. Measure the resistance. If it is ∞, replace the fuser unit thermistor (see page 1-6-22). Check and reinstall if necessary. Check for continuity. If none, replace the fuser unit thermostat (see page 1-6-22). Check and reinstall if necessary. Check for continuity. If none, replace the fuser unit heater M or S (see page 1-6-20).

• Code: 6410
• Description: Fuser unit connector insertion problem
  • Absence of the fuser unit is detected continuously for 1500 ms while there is no error on the printer.
• Causes: Fuser unit connector inserted incorrectly. Defective fuser unit connector.
• Remedy: Reinsert the fuser unit connector if necessary. Replace the fuser unit.

• Code: 6420
• Description: Broken fuser unit thermistor wire
  • The fuser temperature remains at 0 °C/32 °F for 30 s continuously when the fuser heater is on. co
• Causes: Poor contact in the fuser unit thermistor connector terminals. Broken fuser unit thermistor wire.
• Remedy: Check the connection of connector CN10 on the engine controller PWB and the continuity across the connector terminals. Repair or replace if necessary. Measure the resistance. If it is ∞, replace the fuser unit thermistor.

• Code: 7400
• 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 printer.
• 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: 7410
• Description: Drum unit connector insertion problem
  • Absence of the drum unit is detected continuously for 1500 ms while there is no error on the printer.
• Causes: Drum unit connector inserted incorrectly. Defective drum unit connector.
• Remedy: Reinsert the drum unit connector if necessary. Replace the drum unit.

• Code: 7800
• Description: Broken external temperature thermistor wire
  • The input voltage is above 4.5 V.n unit
• Causes: Poor contact in the humidity sensor board 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 board.

• Code: 7810
• Description: Short-circuited external temperature thermistor
  • The input voltage is below 0.5 V.
• Causes: Poor contact in the humidity sensor board 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 board.