• Code: 4501
• Description: Laser malfunction
  • SOS signal is not detected even after the lapse of a given period of time after starting the laser output. • SOS signal is not detected for a given period of time during printing.
• Causes: • PH unit • Printer control board (PRCB)
• Remedy: 1 Check the connector between PH unit-relay CN73- PRCB CN5 for proper connection and correct as necessary. - - 2 Replace the PH unit - - 3 Replace PRCB

• Code: 4801
• Description: Main unit board failure
  A faulty combination of the printer control board (PRCB) and the MFP board (MFPB) is detected.
• Causes: • MFP board (MFPB) • Printer control board (PRCB)
• Remedy: 1 Reboot the machine. - - 2 Replace MFPB - - 3 Replace PRCB

• Code: 4802
• Description: Main unit backup data miscompare
  The replacement of the printer control board is detected.
• Causes: Printer control board (PRCB)
• Remedy: 1 1. Call the Service mode to the screen. 2. Touch [Security Service Mode]. 3. Touch [Engine Data Backup]. 4. Touch [Engine Data Reflect Mode], and touch [OK]. 5. Check that the result “OK” appears. 6. Turn OFF the main power switch and turn it ON again more than 10 seconds after. - - 2 Update the firmware. - - 3 If the above actions do not solve the problem, contact KM.

• Code: 4901
• Description: FW/OS integrity verification error
  • NG results from verification of the hash value of the controller FW. • Faulty, damaged, or illegally written ROM data
• Causes: • MFP board (MFPB) • SSD board (SSDB)
• Remedy: 1 Reboot the machine. - - 2 Update the firmware. - - 3 Check the MFPB for proper connection and correct as necessary. - - 4 Check the SSDB for proper connection and correct as necessary. 5 Replace SSD 6 Replace MFPB

• Code: 5102
• Description: Main motor failure
  The motor lock signal remains HIGH for a predetermined continuous period of time while the motor remains stationary.
• Causes: • Main motor (M1) • Printer control board (PRCB)
• Remedy: 1 Check the connector between M1-PRCB CN9 for proper connection and correct as necessary. - - 2 M1 operation check PRCB CN9-3 to 6 15-B 3 Replace M1 - - 4 PRCB F9 conduction check - - 5 Replace PRCB

• Code: 5307
• Description: UFP fan motor failure
  The fan lock signal remains HIGH for a predetermined continuous period of time while the fan is turning.
• Causes: • UFP fan motor (FM5) • Printer control board (PRCB)
• Remedy: 1 Check the connector between FM5-relay CN158-relay CN90-PRCB CN13 for proper connection and correct as necessary. - - 2 Check the fan for possible overload and correct as necessary. - - 3 FM5 operation check EXCB CN13-1 (OUT) EXCB CN13-3 (LOCK) 15-F 4 Replace FM5 - - 5 PRCB F2 conduction check - - 6 Replace PRCB

• Code: 5351
• Description: DC power supply fan motor failure
  The fan lock signal remains HIGH for a predetermined continuous period of time while the fan is turning.
• Causes: • DC power supply fan motor (FM1) • Printer control board (PRCB)
• Remedy: 1 Check the connector between FM1-relay CN304- PRCB CN3 for proper connection and correct as necessary. - - 2 Check the fan for possible overload and correct as necessary. - - 3 FM1 operation check PRCB CN3-10 (OUT) PRCB CN3-12 (LOCK) 7-L 4 Replace FM1 - - 5 PRCB F2 conduction check - - 6 Replace PRCB

• Code: 5353
• Description: Cooling fan motor/2 failure
  The fan lock signal remains HIGH for a predetermined continuous period of time while the fan is turning.
• Causes: • Cooling fan motor/2 (FM6)ning. • Printer control board (PRCB)
• Remedy: 1 Check the connector between FM6-relay CN302- PRCB CN3 for proper connection and correct as necessary. - - 2 Check the fan for possible overload and correct as necessary. - - 3 FM6 operation check PRCB CN3-4 (OUT) PRCB CN3-6 (LOCK) 7-K 4 Replace FM6 - - 5 PRCB F2 conduction check - - 6 Replace PRCB