• Code: C6600
• Description: Fuser belt rotation error
• Causes: The belt rotation pulse is not input for 1.8s continuously.
• Remedy: 1 Reinstalling the fuser unit The drawer connector of the fuser unit is not properly inserted. Check if the pins of the drawer connector of the fuser unit do not bend. If it bend, replace the fuser unit. When the pins are proper, reinstall the fuser unit so that the drawer connector firmly connects. Fuser Unit Replacement 2 Replacing the fuser unit The fuser unit parts such as the fuser belt, the belt rotation detecting system, or the belt rotation sensor are faulty Replace the fuser unit. Fuser Unit Replacement 3 Applying the grease The load increases due to the lack of grease on the bushing or the gears for the fuser motor. Check the fuser motor operation by executing U030 [Fuser], and apply the grease to the bushing or the gear if it does not rotate smoothly. U030 Execution 4 Checking the wire The wire is not properly connected or is faulty. Reinsert the following wire connectors, and replace the wires if there is no continuity.• Fuser motor - Feed drive PWB• Feed drive PWB - Engine PWB• Feed image PWB - Engine PWB Electrical Diagram of PWBs 5 Firmware upgrade The firmware is not the latest version. Upgrade the engine firmware to the latest version Firmware Upgrade 6 Replacing the engine PWB The engine PWB is faulty. Replace the engine PWB. Engine PWB Replacement 7 Replacing the feed drive PWB The feed drive PWB is faulty. Replace the feed drive PWB. 8 Replacing the feed image PWB The feed image PWB is faulty. Replace the feed image PWB. 9 Replacing the fuser drive gear The fuser drive gear is faulty. Replace the fuser drive gear.

• Code: C6610
• Description: Fuser pressure release sensor error
• Causes: 1. The fuser pressure release sensor does not turn off after passing 3s from the instruction to reduce the fuser pressure by the fuser release motor, or to relocate the paper jam processing position.2. The fuser pressure release sensor does not turn on after passing 6s from the instruction to increase the fuser pressure by the fuser release motor.3. The lock-up signal of the fuser release motor is low for 200ms. (However, when shifting to the paper jam processing mode, the fuser release motor is stopped but the service call error does not appear if it is in between the stop position and the position in front of the stop position by 500ms.)
• Remedy: 1 Reinstalling the fuser unit The drawer connector of the fuser unit is not properly inserted. Check if the pins of the drawer connector of the fuser unit do not bend. If it bend, replace the fuser unit. When the pins are proper, reinstall the fuser unit so that the drawer connector firmly connects. Fuser Unit Replacement 2 Checking the wire The wire is not properly connected or is faulty. Execute U030 [Fuser Release] to check the fuser release motor operation. If it does not operate properly, reinsert the following wire connectors. Then, replace the wires if there is no continuity.• Fuser release motor (in the fuser unit) - Feed drive PWB• Feed drive PWB - Engine PWB• Drawer connector of the fuser unit - Feed image PWB• Feed image PWB - Engine PWB Electrical Diagram of PWBs 3 Replacing the fuser unit The fuser unit is faulty at the fuser pressure release mechanism or the fuser pressure release sensor . Replace the fuser unit. Fuser Unit Replacement 4 Firmware upgrade The firmware is not the latest version. Upgrade the engine firmware to the latest version Firmware Upgrade 5 Replacing the feed drive PWB The feed drive PWB is faulty. Replace the feed drive PWB. 6 Replacing the engine PWB The engine PWB is faulty. Replace the engine PWB. Engine PWB Replacement 7 Replacing the feed image PWB The feed image PWB is faulty. Replace the feed image PWB. 8 Replacing the fuser release motor The fuser release motor is faulty. Replace the fuser release motor. Fuser Drive Unit Replacement 9 Replacing the gear in the fuser pressure releasing system at the main unit The gear of the fuser pressure releasing mechanism at the main unit is faulty. Replace the gears in the fuser pressure releasing mechanism at the main unit.

• Code: C6620
• Description: IH core motor rotation error Object: 35ppm or faster color models, and the monochrome models
• Causes: 1. Turning on of the IH position sensor is not detected within 5s after the IH core motor drives while the IH position sensor is off at the home position detecting operation.2. Turning off/on of the IH position sensor is not detected within 5s after the IH core motor drives while the IH position sensor is on at the home position detecting operation.3. Turning off of the IH position sensor is not detected within the specified pulse after the IH core motor drives while the IH position sensor is on when shifting to the small size paper position.
• Remedy: 1 Checking the fuser IH unit The connector of the fuser IH unit is not properly connected. Check if the connector pins of the fuser IH unit do not bend. If the pins bend, fix them.Next, reinstall the fuser IH unit so that the connector firmly connects. 2 Checking the IH positioning sensor The IH positioning sensor is not properly attached. Reattach the IH positioning sensor. 3 Cleaning the IH positioning sensor The IH positioning sensor cannot detect properly since it is dirty. Clean the IH positioning sensor. 4 Checking the wire The wire is not properly connected or is faulty. Reinsert the following wire connectors, and replace the wires when they have no continuity.• IH core motor (Fuser IH unit) - Feed drive PWB• Feed drive PWB - Engine PWB Electrical Diagram of PWBs 5 Replacing the fuser IH unit The IH positioning sensor or the IH core motor is faulty. Replace the fuser IH unit. Fuser IH Unit Replacement 6 Firmware upgrade The firmware is not the latest version. Upgrade the engine firmware to the latest version Firmware Upgrade 7 Replacing the feed image PWB The feed image PWB is faulty. Replace the feed image PWB. 8 Replacing the engine PWB The engine PWB is faulty. Replace the engine PWB. Engine PWB Replacement

• Code: C6740
• Description: IH PWB high temperature error (IGBT2)
• Causes: The IGBT temperature acquired from the power microprocessor detected is 115°C / 239°F or more for 1s continuously.
• Remedy: 1 Checking the IH PWB fan motor The connection of the IH PWB fan motor, or the IH PWB fan motor is faulty. Execute U037 [IH PWB] and check the IH PWB fan motor operation.If it does not properly operate, go to step 2 "Connecting the IH PWB fan motor". If it properly operates, go to step 3 "Replacing the IH PWB fan motor". U037 Execution 2 Connecting the IH PWB fan motor The connector of the IH PWB fan motor wire is not inserted securely. Reinsert the connector of the IH PWB fan motor. 3 Replacing the IH PWB fan motor The IH PWB fan motor is faulty. Replace the IH PWB fan motor. Fan Motors Attachable Direction 4 Checking the wire The wire is not properly connected or is faulty. Reinsert the following wire connectors, and replace the wire when it has no continuity.• IH PWB - Engine PWB Electrical Diagram of PWBs 5 Replacing the IH PWB The IH PWB is faulty. Replace the IH PWB. IH PWB Replacement 6 Firmware upgrade The firmware is not the latest version. Upgrade the engine firmware to the latest version Firmware Upgrade 7 Replacing the engine PWB The engine PWB is faulty. Replace the engine PWB. Engine PWB Replacement

• Code: C6760
• Description: Fuser IH input excessive electric current error
• Causes: The input current acquired from the power microprocessor continued at 20A or more (for 120V), or 10A or more (for 220-240V) for 200ms.
• Remedy: 1 Checking the fuser unit The fuser belt is faulty. Detach the fuser unit and check if the fuser belt is not faulty. If there is any damage, replace the fuser unit. Fuser Unit Replacement 2 Checking the wire The wire is not properly connected or is faulty. Reinsert the following wire connectors, and replace the wire when it has no continuity.• IH PWB - Engine PWB Electrical Diagram of PWBs 3 Firmware upgrade The firmware is not the latest version. Upgrade the engine firmware to the latest version Firmware Upgrade 4 Replacing the IH PWB The IH PWB is faulty. Replace the IH PWB. IH PWB Replacement 5 Replacing the fuser unit The fuser unit is faulty. Replace the fuser unit. Fuser Unit Replacement 6 Replacing the engine PWB The engine PWB is faulty. Replace the engine PWB. Engine PWB Replacement

• Code: C6770
• Description: IH low power error
• Causes: The IH PWB detects 30% or less of the setting power value for the certain time after the fuser heating is started.
• Remedy: 1 Checking the wire The wire is not properly connected or is faulty. Reinsert the following wire connectors, and replace the wires when they have no continuity.• Fuser IH unit - IH PWB• IH PWB - Engine PWB Electrical Diagram of PWBs 2 Replacing the IH PWB The IH PWB is faulty. Replace the IH PWB. IH PWB Replacement 3 Firmware upgrade The firmware is not the latest version. Upgrade the engine firmware to the latest version Firmware Upgrade 4 Replacing the engine PWB The engine PWB is faulty. Replace the engine PWB. Engine PWB Replacement 5 Replacing the feed image PWB The feed image PWB is faulty. Replace the feed image PWB. 6 Checking the cause depending on the input power The input power is improper. Change the input power. 7 Replacing the fuser IH unit The fuser IH unit is faulty. (The coil is broken.) Replace the fuser IH unit. Fuser IH Unit Replacement

• Code: C6900
• Description: Edge fan motor error
• Causes: The lock-up was detected for 20s continuously when driving the fan motor.
• Remedy: 1 Checking the edge fan motor The wire is not properly connected or is faulty. Execute U037 [Fuser Edge], and reinsert the connector of the paper conveying unit (edge fan motor) into the relay connector at the main unit side if the edge fan motor does not operate properly. U037 Execution 2 Checking the wire The wire is not properly connected or is faulty. Reinsert the following wire connectors, and replace the wires when they have no continuity.• Edge fan motor - Feed drive PWB• Feed drive PWB - Engine PWB Electrical Diagram of PWBs 3 Replacing the edge fan motor The edge fan motor is faulty. Replace the edge fan motor. Fan Motors Attachable Direction 4 Firmware upgrade The firmware is not the latest version. Upgrade the engine firmware to the latest version Firmware Upgrade 5 Replacing the feed drive PWB The feed drive PWB is faulty. Replace the feed drive PWB. 6 Replacing the engine PWB The engine PWB is faulty. Replace the engine PWB. Engine PWB Replacement

• Code: C6910
• Description: Engine firmware unexpected error
• Causes: 1. The engine stabilization control was continued for 1 hour.2. The paper feed motor does not drive after passing 3s or more when driving the drum motor or the developer BK/belt motor.3. Only the high-voltage remote signal turned on while the drum was stopped.4. The main charger bias turned off while the developer bias was on.
• Remedy: 1 Resetting the main power The power startup delays. Turn the power switch and the main power switch off . After 5s passes, turn the main power switch and the power switch on. 2 Firmware upgrade The firmware is not the latest version. Upgrade the engine firmware to the latest version Firmware Upgrade 3 Checking the engine PWB The engine PWB is not properly attached or connected. Retighten the screws securing the engine PWB so that it can ground securely, and reinsert the connectors all the way. Engine PWB Replacement 4 Replacing the engine PWB The engine PWB is faulty. Replace the engine PWB. Engine PWB Replacement