• Code: 6F
• Description: Fuser unit error (The center or side thermistors detect extremely high temperature.)
• Causes: 1 Harness connection failure between fuser unit connector and eject front sensor PCB ASSY. 2 Harness connection failure between eject front sensor PCB ASSY and main PCB ASSY. 3 Fuser unit failure. 4 Low-voltage power supply PCB failure. 5 Eject front sensor PCB failure. 6 Main PCB failure.
• Remedy: 1 Harness connection failure between fuser unit connector and eject front sensor PCB ASSY Check the harness connection between the fuser unit connector and eject front sensor PCB ASSY, and reconnect it. 2 Harness connection failure between eject front sensor PCB ASSY and main PCB ASSY Check the harness connection between the eject front sensor PCB ASSY and main PCB ASSY, and reconnect it. 3 Fuser unit failure Replace the fuser unit. 4 Low-voltage power supply PCB failure Replace the low-voltage power supply PCB ASSY. 5 Eject front sensor PCB failure Replace the eject front sensor PCB ASSY. 6 Main PCB failure Replace the main PCB ASSY.

• Code: 70
• Description: Fuser/Eject drive motor error
• Causes: 1 Harness connection failure of fuser/eject drive motor. 2 Harness connection failure of fuser/eject drive motor sensor PCB ASSY. 3 Fuser/eject drive motor failure. 4 Fuser/eject drive motor sensor PCB ASSY failure. 5 Engine PCB failure. 6 Main PCB failure.
• Remedy: 1 Harness connection failure of fuser/eject drive motor Check the harness connection of the fuser/eject drive motor and reconnect it. 2 Harness connection failure of fuser/eject drive motor sensor PCB ASSY Check the harness connection of the fuser/eject drive motor sensor PCB ASSY and reconnect it. 3 Fuser/eject drive motor failure Replace the fuser/eject drive motor. 4 Fuser/eject drive motor sensor PCB ASSY failure Replace the fuser/eject drive motor sensor PCB ASSY. 5 Engine PCB failure Replace the engine PCB ASSY. 6 Main PCB failure Replace the main PCB ASSY.

• Code: 73
• Description: Recording ASIC read/write error
• Causes: 1 Harness connection failure of LED head control PCB ASSY. 2 LED head control PCB failure. 3 Main PCB failure.
• Remedy: 1 Harness connection failure of LED head control PCB ASSY Check the harness connection between the main PCB ASSY and LED head control PCB ASSY, and reconnect them. 2 LED head control PCB failure Replace the LED head control PCB ASSY. 3 Main PCB failure Replace the main PCB ASSY.

• Code: 74
• Description: Toner of the color which is being used reaches the end of life while printing.
• Causes: 1 Toner/new sensor PCB failure. 2 Engine PCB failure.
• Remedy: 1 Toner/new sensor PCB failure Check the sensor performance following the procedure described in “Function code 32”. If any problem occurs, replace the toner/new sensor PCB ASSY. 2 Engine PCB failure Replace the engine PCB ASSY.

• Code: 75
• Description: Machine cooling down inside
• Causes: 1 Dirt or dust on drum unit electrodes. 2 HVPS control PCB failure. 3 High-voltage power supply PCB failure. 4 Main PCB failure.
• Remedy: 1 Dirt or dust on drum unit electrodes Clean the electrodes of the drum unit, belt unit and main body. (Refer to Fig. 3-3, Fig-3-4 (next page) and Fig. 3-6 (P3-33).) 2 HVPS control PCB failure Replace the HVPS control PCB ASSY. 3 High-voltage power supply PCB failure Replace the high-voltage power supply PCB ASSY. 4 Main PCB failure Replace the main PCB ASSY.

• Code: 76
• Description: Fuser unit error (The center thermistor detects rapid temperature rising.)
• Causes: 1 Harness connection failure between fuser unit connector and eject front sensor PCB ASSY. 2 Harness connection failure between eject front sensor PCB ASSY and main PCB ASSY. 3 Fuser unit failure. 4 Low-voltage power supply PCB failure. 5 Eject front sensor PCB failure. 6 Main PCB failure.
• Remedy: 1 Harness connection failure between fuser unit connector and eject front sensor PCB ASSY Check the harness connection between the fuser unit connector and eject front sensor PCB ASSY, and reconnect it. 2 Harness connection failure between eject front sensor PCB ASSY and main PCB ASSY Check the harness connection between the eject front sensor PCB ASSY and main PCB ASSY, and reconnect it. 3 Fuser unit failure Replace the fuser unit. 4 Low-voltage power supply PCB failure Replace the low-voltage power supply PCB ASSY. 5 Eject front sensor PCB failure Replace the eject front sensor PCB ASSY. 6 Main PCB failure Replace the main PCB ASSY.

• Code: 78
• Description: Fuser unit error (The center thermistor detects rapid temperature falling.)
• Causes: 1 Harness connection failure between fuser unit connector and eject front sensor PCB ASSY. 2 Harness connection failure between eject front sensor PCB ASSY and main PCB ASSY. 3 Fuser unit failure. 4 Low-voltage power supply PCB failure. 5 Eject front sensor PCB failure. 6 Main PCB failure.
• Remedy: 1 Harness connection failure between fuser unit connector and eject front sensor PCB ASSY Check the harness connection between the fuser unit connector and eject front sensor PCB ASSY, and reconnect it. 2 Harness connection failure between eject front sensor PCB ASSY and main PCB ASSY Check the harness connection between the eject front sensor PCB ASSY and main PCB ASSY, and reconnect it. 3 Fuser unit failure Replace the fuser unit. 4 Low-voltage power supply PCB failure Replace the low-voltage power supply PCB ASSY. 5 Eject front sensor PCB failure Replace the eject front sensor PCB ASSY. 6 Main PCB failure Replace the main PCB ASSY.

• Code: 7D
• Description: Dirt on drum unit
• Causes: 1 Dirt or dust on drum unit electrodes. 2 HVPS control PCB failure. 3 High-voltage power supply PCB failure. 4 Main PCB failure.
• Remedy: 1 Dirt or dust on drum unit electrodes Clean the electrodes of the drum unit, belt unit and main body. (Refer to Fig. 3-3, Fig-3-4 (next page) and Fig. 3-6 (P3-33).) 2 HVPS control PCB failure Replace the HVPS control PCB ASSY. 3 High-voltage power supply PCB failure Replace the high-voltage power supply PCB ASSY. 4 Main PCB failure Replace the main PCB ASSY.