• Code: C-3903
• Description: Thermistor /1 (TH1) high temperature abnormality 1 (hardware). TH1 detects the fusing abnormality detection signal 2.
• Causes: • Fusing temperature sensor /1 (TH1) • Fusing heater lamp /1 (L1) • Fusing heater lamp /2 (L2) • Printer control board (PRCB) • AC drive board (ACDB)
• Remedy: 1. Check the fusing heater lamp /1 and /2 (L1 and L2), and clean/repair them if any abnormality. (Wiring diagram: Main body (1/4): 2-A, Main body (1/4): 3-A) 2. Check the connector connection and the wiring between PRCB and TH1, and repair it if any abnormality. 3. Check the connector connection and the wiring between ACDB and L1/L2, and repair it if any abnormality. 4. Check TH1 to see the installed position or distance to the fusing roller /Up, and adjust/replace it if any abnormality. (Wiring diagram: Main body (3/4): 11-I (S1/S2), 11-F (S3)). 5. Replace TH1. 6. Replace L1 and L2. 7. Replace PRCB. 8. Replace ACDB.

• Code: C-3904
• Description: Thermistor /3 (TH3) high temperature abnormality (hardware). TH3 detects the fusing abnormality detection 5.
• Causes: • Fusing temperature sensor /3 (TH3) • Fusing heater lamp /3 (L3) • Printer control board (PRCB) • AC drive board (ACDB)
• Remedy: 1. Check the fusing heater lamp /3 (L3), and repair it if any abnormality. (Wiring diagram: Main body (1/4): 4-A) 2. Check the connector connection and the wiring between PRCB and TH1, and repair it if any abnormality. 3. Check the connector connection and the wiring between ACDB and L3, and repair it if any abnormality. 4. Check TH3 to see the installed position or distance to the fusing roller /Up, and adjust/replace it if any abnormality. (Wiring diagram: Main body (3/4): 10-I (S1/S2), 10-F (S3)) 5. Replace TH3. 6. Replace L3. 7. Replace PRCB. 8. Replace ACDB.

• Code: C-3905
• Description: Thermistor /1 (TH1) high temperature abnormality 1 (hardware). TH1 detects the fusing abnormality detection signal 3.
• Causes: • Fusing temperature sensor /1 (TH1) • Fusing heater lamp /1 (L1) • Fusing heater lamp /2 (L2) • Printer control board (PRCB) • AC drive board (ACDB)
• Remedy: 1. Check the fusing heater lamp /1 and /2 (L1 and L2), and clean/repair them if any abnormality. (Wiring diagram: Main body (1/4): 2-A, Main body (1/4): 3-A) 2. Check the connector connection and the wiring between PRCB and TH1, and repair it if any abnormality. 3. Check the connector connection and the wiring between ACDB and L1/L2, and repair it if any abnormality. 4. Check TH1 to see the installed position or distance to the fusing roller /Up, and adjust/replace it if any abnormality. (Wiring diagram: Main body (3/4): 11-I (S1/S2), 11-F (S3)). 5. Replace TH1. 6. Replace L1 and L2. 7. Replace PRCB. 8. Replace ACDB.

• Code: C-3906
• Description: Thermistor /3 (TH3) high temperature abnormality (hardware). TH3 detects the fusing abnormality detection 6.
• Causes: • Fusing temperature sensor /3 (TH3) • Fusing heater lamp /3 (L3) • Printer control board (PRCB) • AC drive board (ACDB)
• Remedy: 1. Check the fusing heater lamp /3 (L3), and repair it if any abnormality. (Wiring diagram: Main body (1/4): 4-A) 2. Check the connector connection and the wiring between PRCB and TH1, and repair it if any abnormality. 3. Check the connector connection and the wiring between ACDB and L3, and repair it if any abnormality. 4. Check TH3 to see the installed position or distance to the fusing roller /Up, and adjust/replace it if any abnormality. (Wiring diagram: Main body (3/4): 10-I (S1/S2), 10-F (S3)) 5. Replace TH3. 6. Replace L3. 7. Replace PRCB. 8. Replace ACDB.

• Code: C-4301
• Description: Image processing cooling fan (FM12) rotation abnormality + 24V power abnormality. The abnormal status is detected twice in succession after FM12 was turned ON. At this time, an error detection signal (24V cut off) is detected.
• Causes: DC power supply /2 (DCPS/2)
• Remedy: 1. Check the connector connection and the wiring between ACDB and DCPS /2, and repair it if any abnormality. 2. Replace DCPS /2

• Code: C-4303
• Description: Image processing cooling fan (FM12) rotation abnormality 1. The FM12 EM error detection signal is detected twice in succession within a specified period of time after FM12 was turned ON. However, error detection signal (24V cut off) is not detected.
• Causes: • Image processing cooling fan (FM12) • Printer control board (PRCB)
• Remedy: 1. Check the connector connection and the wiring between PRCB and the fan, and repair it if any abnormality. 2. Rotate the fan or I/O by hand, and repair it if any abnormality. (Wiring diagram: Main body (2/4): 8-A) 3. Replace FM12. 4. Replace PRCB.

• Code: C-4304
• Description: Image processing cooling fan (FM12) rotation abnormality 2. When the print is started, the EM signal of FM12 turns ON.
• Causes: • Image processing cooling fan (FM12) • Printer control board (PRCB) • AC drive board (ACDB)
• Remedy: 1. Check the connector connection and the wiring between PRCB and the fan, and repair it if any abnormality. 2. Check the connector connection and the wiring between ACDB and the fan, and repair it if any abnormality. 3. Rotate the fan or I/O by hand, and repair it if any abnormality. (Wiring diagram: Main body (2/4): 8-A) 4. Replace FM12. 5. Replace PRCB. 6. Replace ACDB.

• Code: C-4305
• Description: Charger suction fan (FM3) rotation abnormality + 24V power abnormality. The abnormal status is detected twice in succession after FM3 was turned ON. At this time, an error detection signal (24V cut off) is detected.
• Causes: DC power supply /2 (DCPS/2)
• Remedy: 1. Check the connector connection and the wiring between ACDB and DCPS /2, and repair it if any abnormality. 2. Replace DCPS /2