• Code: C7914
• Description: Developer unit Y EEPROM error Object: Color models
• Causes: 1. No response from the device is detected for 5s or more 5 times continuously when reading / writing the data.2. The reading data of 2 points mismatches 8 times continuously.3. The reading data and the writing data mismatch 8 times continuously.
• Remedy: 1 Resetting the main power The data stored in the EEPROM in the developer unit is faulty. Turn the power switch and the main power switch off . After 5s passes, turn the main power switch and the power switch on. 2 Reinstalling the developer unit The developer unit is not properly installed. Reinstall developer unit Y so that the connector firmly connects. Developer Unit Replacement 3 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.• Drum/developer relay PWB - Feed image PWB• Feed image PWB - Engine PWB Electrical Diagram of PWBs 4 Developer unit replacement The EEPROM in the developer unit is faulty. Replace the developer unit Y. Developer Unit Replacement 5 Firmware upgrade The firmware is not the latest version. Upgrade the engine firmware to the latest version Firmware Upgrade 6 Replacing the drum/developer relay PWB The drum/developer relay PWB is faulty. Replace the drum/developer relay PWB. Drum/ Developer Relay PWB Replacement 7 Checking the feed image PWB The feed image PWB is faulty. Replace the feed image PWB.

• Code: C7941
• Description: LSU EEPROM error For the 35 ppm or faster color models, this is the LSU EEPROM error when the access to Cyan or Yellow is faulty
• Causes: 1. The reading data of 2 points mismatches 8 times continuously.2. The reading data and the writing data mismatch 8 times continuously.
• Remedy: 1 Resetting the main power The EEPROM data in the LSU is faulty. Turn the power switch and the main power switch off . After 5s passes, turn the main power switch and the power switch on. 2 Checking the FFC The FFC is not properly connected, or it is faulty. Reconnect the following FFC. When the FFC terminals are peeled off or deformed or the FFC is broken, replace the FFC.• APC PWB (LSU) - Engine PWB Electrical Diagram of PWBs 3 LSU replacement The APC PWB (LSU) is faulty. Replace the LSU. LSU Replacement 4 Firmware upgrade The firmware is not the latest version. Upgrade the engine firmware to the latest version Firmware Upgrade

• Code: C7942
• Description: LSU EEPROM error 2 Object: 35ppm or faster color models
• Causes: 1. The reading data of 2 points mismatches 8 times continuously.2. The reading data and the writing data mismatch 8 times continuously
• Remedy: 1 Resetting the main power The EEPROM data in the LSU is faulty. Turn the power switch and the main power switch off . After 5s passes, turn the main power switch and the power switch on. 2 Checking the FFC The FFC is not properly connected, or it is faulty. Reconnect the following FFC. When the FFC terminals are peeled off or deformed or the FFC is broken, replace the FFC.• APC PWB (LSU) - Engine PWB Electrical Diagram of PWBs 3 LSU replacement The APC PWB (LSU) is faulty. Replace the LSU. LSU Replacement 4 Firmware upgrade The firmware is not the latest version. Upgrade the engine firmware to the latest version Firmware Upgrade

• Code: C7970
• Description: Weight detection sensor error
• Causes: The sensor output value was at the specified value (54) or less and that state continued for 500ms.
• Remedy: 1 Reinstalling the waste toner box The waste toner box is not properly installed. Reinstall the waste toner box into the main unit slowly, and then check if it moves vertically. Waste Toner Box Replacement 2 Checking the wire The relay connector which connects between the engine PWB and the waste toner motor / weight detection sensor is loose or disconnected since the wire of the relay connector was stretched excessively at the backside of the waste toner box unit during the maintenance work. Rearrange the wire alignment so that the wire of the relay connector at the waste toner box unit backside is not excessively stretched. Then, reconnect the relay connector. Connection of Relay Connector of Waste Toner Box Unit 3 Checking the weight detection sensor and the actuator The weight detection sensor is not properly connected, or the actuator is not properly attached. Reconnect the weight detection sensor, or correct the position of the actuator. 4 Checking the weight detection spring The weight detection spring is not properly attached. Reattach the weight detection spring. 5 Cleaning the weight detection sensor and the neighboring parts The weight detection sensor and the neighboring parts are dirty. Clean the weight detection sensor and the neighboring parts with an air-blower. 6 Executing U155 The calibration of the weight detection sensor was not executed properly. Execute the waste toner calibration at U155. U155 Execution 7 Replacing the waste toner box The waste toner box is faulty. Replace the waste toner box. Waste Toner Box Replacement 8 Firmware upgrade The engine firmware is faulty. Upgrade the engine firmware to the latest version Firmware Upgrade 9 Replacing the engine PWB The engine PWB is faulty. Replace the engine PWB. Engine PWB Replacement

• Code: C8010
• Description: PH motor error 1 Object: 4000-sheet finisher or 1000-sheet finisher with the punch unit
• Causes: 1. The PH home position sensor does not turn on after passing 200ms when driving the PH motor.2. The pulse plate does not count the specified pulse after passing 300ms since the punch operation was started.
• Remedy: 1 Checking the punch unit The punch unit is not assembled properly. If the punch unit is not shifted manually, repair the part that restricts the operation. 2 Checking the punch cam drive components The punch cam drive components are not properly attached, or they are faulty. Reattach the punch cam drive components. Then, replace them if they are not fixed. 3 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.• PH motor - PH main PWB• PH main PWB - DF main PWB Electrical Diagram of PWBs 4 Replacing the PH motor The PH motor is faulty. Replace the PH motor if it does not operate properly when checking the operation at U240. U240 Execution 5 Checking the PH home position sensor The PH home position sensor is not properly attached, or it is faulty. Execute U241 to check the PH home position sensor operation. If it does not operate properly, reattach it.When it is not fixed, replace the PH home position sensor. U241 Execution 6 Firmware upgrade The firmware is not the latest version. Upgrade the PH firmware to the latest version. Firmware Upgrade 7 Replacing the PH main PWB The PH main PWB is faulty. Replace the PH main PWB. 8 Replacing the DF main PWB The DF main PWB is faulty. Replace the DF main PWB. DF Main PWB Replacement

• Code: C8020
• Description: PH motor error 2 Object: 4000-sheet finisher or 1000-sheet finisher with the punch unit
• Causes: The positioning alignment of the home position is not completed within 3s when initializing or waiting the home position
• Remedy: 1 Checking the punch unit The punch unit is not assembled properly. If the punch unit is not shifted manually, repair the part that restricts the operation. 2 Checking the punch cam drive components The punch cam drive components are not properly attached, or they are faulty. Reattach the punch cam drive components. Then, replace them if they are not fixed. 3 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.• PH motor - PH main PWB• PH main PWB - DF main PWB Electrical Diagram of PWBs 4 Replacing the PH motor The PH motor is faulty. Replace the PH motor if it does not operate properly when checking the operation at U240. U240 Execution 5 Firmware upgrade The firmware is not the latest version. Upgrade the PH firmware to the latest version. Firmware Upgrade 6 Replacing the PH main PWB The PH main PWB is faulty. Replace the PH main PWB. 7 Replacing the DF main PWB The DF main PWB is faulty. Replace the DF main PWB. DF Main PWB Replacement

• Code: C8030
• Description: PH motor error 3 Object: 4000-sheet finisher or 1000-sheet finisher with the punch unit
• Causes: The home position detection does not turn off within 50ms when initializing the home position.
• Remedy: 1 Checking the punch unit The punch unit is not assembled properly. If the punch unit is not shifted manually, repair the part that restricts the operation. 2 Checking the punch cam drive components The punch cam drive components are not properly attached, or they are faulty. Reattach the punch cam drive components. Then, replace them if they are not fixed. 3 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.• PH motor - PH main PWB• PH main PWB - DF main PWB Electrical Diagram of PWBs 4 Replacing the PH motor The PH motor is faulty. Replace the PH motor if it does not operate properly when checking the operation at U240. U240 Execution 5 Firmware upgrade The firmware is not the latest version. Upgrade the PH firmware to the latest version. Firmware Upgrade 6 Replacing the PH main PWB The PH main PWB is faulty. Replace the PH main PWB. 7 Replacing the DF main PWB The DF main PWB is faulty. Replace the DF main PWB. DF Main PWB Replacement

• Code: C8090
• Description: DF paddle motor error
• Causes: 1. The DF paddle sensor does not turn on after passing 1s when driving the DF paddle motor.2. The DF paddle sensor does not turn off when driving the DF paddle motor for 1s.
• Remedy: 1 Checking the DF paddle drive components The DF paddle drive components are not properly attached, or it is faulty. Reattach the DF paddle drive components. Then, replace them if they are not fixed. 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.• DF paddle motor - DF main PWB• DF paddle sensor - DF main PWB Electrical Diagram of PWBs 3 Replacing the DF paddle motor The DF paddle motor is faulty. Replace the DF paddle motor if it does not operate properly when checking the operation at U240. U240 Execution 4 Replacing the DF paddle sensor The DF paddle sensor is faulty. Replace the DF paddle sensor if it does not operate properly when checking the operation at U241. U241 Execution 5 Replacing the DF main PWB The DF main PWB is faulty. Replace the DF main PWB. DF Main PWB Replacement