• Code: C7520
• Description: Shorted drum thermistor • The drum thermistor input voltage is 1.2 V or less when the front cover is closed.
• Causes: Broken drum thermistor wire. Defective main PCB.
• Remedy: Measure the resistance. If it is 0 Ω , replace the drum thermistor. Replace the main PCB and check for correct operation.

• Code: C7530
• Description: Broken drum heater wire • The drum temperature does not change within 5 minutes of the drum heater turning on.
• Causes: Broken drum heater wire. Poor contact in the drum heater connector terminals.
• Remedy: Check for continuity within the drum heater. If none, replace the drum heater. Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable.

• Code: C7800
• Description: Broken external temperature thermistor • The input voltage is 4.5 V or more.
• Causes: Poor contact in the humidity sensor PCB connector terminals. Defective external temperature thermistor.
• Remedy: Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable. Replace the humidity sensor PCB and check for correct operation.

• Code: C7810
• Description: Short-circuited external temperature thermistor • The input voltage is 0.5 V or less.
• Causes: Poor contact in the humidity sensor PCB connector terminals. Defective external temperature thermistor.
• Remedy: Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable. Replace the humidity sensor PCB and check for correct operation.

• Code: C8010
• Description: Paper conveying motor problem • The LOCK signal of the paper conveying motor is detected for more than 500 ms while the paper conveying motor is operating. However, the first 1 s after the paper conveying motor is turned on is excluded from detection.
• Causes: Loose connection of the paper conveying motor connector. Defective paper conveying motor. Defective finisher main PCB.
• Remedy: Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable. Replace the paper conveying motor and check for correct operation. Replace the finisher main PCB and check for correct operation.

• Code: C8020
• Description: Punch motor problem • The LOCK signal of the punch motor is detected for more than 500 ms while the punch motor is operating. However, the first 1 s after the punch motor is turned on is excluded from detection.
• Causes: Loose connection of the punch motor connector. Defective punch motor. Defective finisher main PCB.
• Remedy: Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable. Replace the punch motor and check for correct operation. Replace the finisher main PCB and check for correct operation.

• Code: C8030
• Description: Upper paper conveying belt problem • During initialization, the intermediate tray upper sliding plate is not detected in the home position within 3 s after the belt returns to the home position. JAM87 is indicated the first time this problem occurs. If the problem reoccurs after initialization when the front cover is opened and closed, the problem is in the upper paper conveying belt. • When the intermediate tray upper sliding plate is operated from the home position, the upper paper conveying belt home position sensor does not turn off within 1 s.
• Causes: Phase shift of the upper paper conveying belt. Malfunction of the upper paper conveying belt motor. Malfunction of the upper paper conveying belt home position sensor. Loose connection of the upper paper conveying belt home position sensor connector. Incorrect insertion of the intermediate tray. Defective finisher main PCB.
• Remedy: Correct the phase of the upper paper conveying belt and check for correct operation. Replace the upper paper conveying belt motor and check for correct operation. Replace the upper paper conveying belt home position sensor and check for correct operation. Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable. Check whether the intermediate tray catches are damaged. Replace the finisher main PCB and check for correct operation.

• Code: C8040
• Description: Lower paper conveying belt problem • During initialization, the intermediate tray lower sliding plate is not detected in the home position within 3 s after the belt returns to the home position. JAM87 is indicated the first time this problem occurs. If the problem reoccurs after initialization when the front cover is opened and closed, the problem is in the lower paper conveying belt. • When the intermediate tray lower sliding plate is operated from the home position, the lower paper conveying belt home position sensor does not turn off within 1 s.
• Causes: Phase shift of the lower paper conveying belt. Malfunction of the lower paper conveying belt motor. Malfunction of the lower paper conveying belt home position sensor. Loose connection of the lower paper conveying belt home position sensor connector. Incorrect insertion of the intermediate tray. Defective finisher main PCB.
• Remedy: Correct the phase of the lower paper conveying belt and check for correct operation. Replace the lower paper conveying belt motor and check for correct operation. Replace the lower paper conveying belt home position sensor and check for correct operation. Reinsert the connector. Also check for continuity within the connector cable. If none, remedy or replace the cable. Check whether the intermediate tray catches are damaged. Replace the finisher main PCB and check for correct operation