• Code: C7902
• Description: Drum C EEPROM error
  No response is issued from the device in reading/writing for 5 ms or more and this problem is repeated five times successively. Mismatch of reading data from two locations occurs eight times successively. Mismatch between writing data and reading data occurs eight times successively.
• Causes: Poor contact in the connector terminals.
  Defective drum PWB C.
• Remedy: Poor contact in the connector terminals. Check the connection of connector YC5 on the sub front PWB and the continuity across the connector terminals. Repair or replace if necessary.
  Defective drum PWB C. Replace the drum unit C.

• Code: C7903
• Description: Drum M EEPROM error
  No response is issued from the device in reading/writing for 5 ms or more and this problem is repeated five times successively. Mismatch of reading data from two locations occurs eight times successively. Mismatch between writing data and reading data occurs eight times successively.
• Causes: Poor contact in the connector terminals.
  Defective drum PWB M.
• Remedy: Poor contact in the connector terminals. Check the connection of connector YC7 on the sub front PWB and the continuity across the connector terminals. Repair or replace if necessary.
  Defective drum PWB M. Replace the drum unit M.

• Code: C7904
• Description: Drum Y EEPROM error No response is issued from the device in reading/writing for 5 ms or more and this problem is repeated five times successively. Mismatch of reading data from two locations occurs eight times successively. Mismatch between writing data and reading data occurs eight times successively.
• Causes: Defective drum PWB Y.
• Remedy: Poor contact in the connector terminals. Check the connection of connector YC3 on the sub front PWB and the continuity across the connector terminals. Repair or replace if necessary.
  Defective drum PWB Y. Replace the drum unit Y.

• Code: C7911
• Description: Developing unit K EEPROM error
  No response is issued from the device in reading/writing for 5 ms or more and this problem is repeated five times successively. Mismatch of reading data from two locations occurs eight times successively. Mismatch between writing data and reading data occurs eight times successively.
• Causes: Poor contact in the connector terminals.
  Defective developing PWB K.
• Remedy: Poor contact in the connector terminals. Check the connection of connector YC4 on the main front PWB and the continuity across the connector terminals. Repair or replace if necessary.
  Defective developing PWB K. Replace the developing unit K.

• Code: C7912
• Description: Developing unit C EEPROM error
  No response is issued from the device in reading/writing for 5 ms or more and this problem is repeated five times successively. Mismatch of reading data from two locations occurs eight times successively. Mismatch between writing data and reading data occurs eight times successively.
• Causes: Poor contact in the connector terminals.
  Defective developing PWB C.
• Remedy: Poor contact in the connector terminals. Check the connection of connector YC6 on the sub front PWB and the continuity across the connector terminals. Repair or replace if necessary.
  Defective developing PWB C. Replace the developing unit C.

• Code: C7913
• Description: Developing unit M EEPROM error
  No response is issued from the device in reading/writing for 5 ms or more and this problem is repeated five times successively. Mismatch of reading data from two locations occurs eight times successively. Mismatch between writing data and reading data occurs eight times successively.
• Causes: Poor contact in the connector terminals.
  Defective developing PWB M.
• Remedy: Poor contact in the connector terminals. Check the connection of connector YC8 on the sub front PWB and the continuity across the connector terminals. Repair or replace if necessary.
  Defective developing PWB M. Replace the developing unit M.

• Code: C7914
• Description: Developing unit Y EEPROM error
  No response is issued from the device in reading/writing for 5 ms or more and this problem is repeated five times successively. Mismatch of reading data from two locations occurs eight times successively. Mismatch between writing data and reading data occurs eight times successively.
• Causes: Poor contact in the connector terminals.
  Defective developing PWB Y.
• Remedy: Poor contact in the connector terminals. Check the connection of connector YC4 on the sub front PWB and the continuity across the connector terminals. Repair or replace if necessary.
  Defective developing PWB Y. Replace the developing unit Y.

• Code: C7950
• Description: High voltage control PWB error
  A communication error from high voltage control PWB is detected 10 times in succession
• Causes: Poor contact in the connector terminals.
  Defective PWB.
• Remedy: Poor contact in the connector terminals. Check the connection of connector YC30 on the engine PWB and the connector on the high voltage control PWB, and the continuity across the connector terminals. Repair or replace if necessary.
  Defective PWB. Replace the high voltage control PWB or engine PWB and check for correct operation.