• Code: C7101
• Description: Black T/C sensor toner density detection error • A normal toner density signal is not entered in the A/D port of CPU (U2) on the engine controller PCB.
• Causes: Defective engine controller PCB. Defective black developer (black developer PCB or black T/C sensor). Defective black developer (black toner feed motor does not rotate in the correct revolution) . Defective harness between engine controller PCB and black developer, or poor contact of the connector terminals.
• Remedy: Replace the engine controller PCB and check for correct operation. Replace the black developer. Replace the black developer. Check the continuity of the harness and the insertion of connectors.

• Code: C7102
• Description: Cyan T/C sensor toner density detection error • A normal toner density signal is not entered in the A/D port of CPU (U2) on the engine controller PCB.
• Causes: Defective engine controller PCB. Defective cyan developer (cyan developer PCB or cyan T/C sensor). Defective cyan developer (cyan toner feed motor does not rotate in the correct revolution) . Defective harness between engine controller PCB and cyan developer, or poor contact of the connector terminals.
• Remedy: Replace the engine controller PCB and check for correct operation. Replace the cyan developer. Replace the cyan developer. Check the continuity of the harness and the insertion of connectors.

• Code: C7103
• Description: Magenta T/C sensor toner density detection error • A normal toner density signal is not entered in the A/D port of CPU (U2) on the engine controller PCB.
• Causes: Defective engine controller PCB. Defective magenta developer (magenta developer PCB or magenta T/C sensor). Defective magenta developer (magenta toner feed motor does not rotate in the correct revolution) . Defective harness between engine controller PCB and magenta developer, or poor contact of the connector terminals
• Remedy: Replace the engine controller PCB and check for correct operation. Replace the magenta developer. Replace the magenta developer. Check the continuity of the harness and the insertion of connectors.

• Code: C7104
• Description: Yellow T/C sensor toner density detection error • A normal toner density signal is not entered in the A/D port of CPU (U2) on the engine controller PCB.
• Causes: Defective engine controller PCB. Defective yellow developer (yellow developer PCB or yellow T/C sensor). Defective yellow developer (yellow toner feed motor does not rotate in the correct revolution) . Defective harness between engine controller PCB and yellow developer, or poor contact of the connector terminals.
• Remedy: Replace the engine controller PCB and check for correct operation. Replace the yellow developer. Replace the yellow developer. Check the continuity of the harness and the insertion of connectors.

• Code: C7301
• Description: Intermediate toner hopper toner feed error • Black toner is not fed in the intermediate toner hopper in the black toner developer from the black toner container within the predetermined period.
• Causes: Defective engine controller PCB. Defective black toner empty sensor PCB. Defective black toner feed clutch. Poor contact of the black toner feed clutch. Defective feed drive PCB. Defective harness between engine controller PCB and black developer, or poor contact of the connector terminals. Defective harness between engine controller PCB and feed drive PCB, or poor contact of the connector terminals.
• Remedy: Replace the engine controller PCB and check for correct operation. Replace the black toner empty sensor PCB. Replace the black toner feed clutch. Check the insertion of connectors. Replace the feed drive PCB. Check the continuity of the harness and the insertion of connectors. Check the continuity of the harness and the insertion of connectors.

• Code: C7600
• Description: Image density sensor detection error • The measured value at the end of color compensation is 255 or more for no image and LED off or the measured value for no image and LED on exceeds the value for any image.
• Causes: Defective engine controller PCB. Defective imege density sensor.
• Remedy: Replace the engine controller PCB and check for correct operation. Replace the image density sensor.

• Code: C7610
• Description: Image density sensor detection error • The measurement result of each density batch at the end of color compensation shows abnormal relation of density in size.
• Causes: Defective engine controller PCB. Defective imege density sensor.
• Remedy: Replace the engine controller PCB and check for correct operation. Replace the image density sensor.

• Code: C7700
• Description: Offset drum sensor detection timeout error • When the drum home position is to be detected, the input level from the offset drum sensor to ASIC (U7) of the engine controller PCB has been gone hign for 5 seconds.
• Causes: Defective drum PCB. Defective engine controller PCB. Defective harness between engine controller PCB and drum unit, or poor contact of the connector terminals.
• Remedy: Replace the drum unit. Replace the engine controller PCB. Check the continuity of the harness and the insertion of connectors.