• Code: 7612
• Description: ID sensor (C) density error
  When the concentration in a bias calibration is unusual.
• Causes: Defective ID sensor. Defective PWB.
• Remedy: Defective ID sensor. Replace the ID sensor.
  Defective PWB. Replace the engine PWB check for correct operation.

• Code: 7613
• Description: ID sensor (M) density error
  When the concentration in a bias calibration is unusual.
• Causes: Defective ID sensor. Defective PWB.
• Remedy: Defective ID sensor. Replace the ID sensor.
  Defective PWB. Replace the engine PWB check for correct operation.

• Code: 7614
• Description: ID sensor (Y) density error
  When the concentration in a bias calibration is unusual.
• Causes: Defective ID sensor. Defective PWB.
• Remedy: Defective ID sensor. Replace the ID sensor.
  Defective PWB. Replace the engine PWB check for correct operation.

• Code: 7620
• Description: ID sensor timing error
  Color registration correction was failed.
• Causes: Defective ID sensor. Defective PWB.
• Remedy: Defective ID sensor. Replace the ID sensor.
  Defective PWB. Replace the engine PWB check for correct operation.

• Code: 7800
• Description: Broken external thermistor wire
  The external thermistor delivers 0.3V or more.
• Causes: Defective connector cable or poor contact in the connector. Defective temperature sensor. Defective PWB.
• Remedy: Defective connector cable or poor contact in the connector. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Temperature sensor and engine PWB (YC29)
  Defective temperature sensor. Replace the temperature sensor.
  Defective PWB. Replace the engine PWB check for correct operation.

• Code: 7810
• Description: Short-circuited external thermistor wire
  external thermistor delivers 3V or more.
• Causes: Defective connector cable or poor contact in the connector. Defective temperature sensor. Defective PWB.
• Remedy: Defective connector cable or poor contact in the connector. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Temperature sensor and engine PWB (YC29)
  Defective temperature sensor. Replace the temperature sensor.
  Defective PWB. Replace the engine PWB check for correct operation.

• Code: 7901
• Description: Drum 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 drum PWB. Defective PWB.
• Remedy: Poor contact in the connector terminals. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Drum unit (K) and drum connect PWB(YC5) drum connect PWB and engine connect PWB (YC4) Engine connect PWB and engine PWB (YC9)
  Defective drum PWB. Replace the drum unit K.
  Defective PWB. Replace the engine PWB check for correct operation.

• Code: 7902
• Description: Drum 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 drum PWB. Defective PWB.
• Remedy: Poor contact in the connector terminals. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Drum unit (C) and drum connect PWB(YC3) drum connect PWB and engine connect PWB (YC4) Engine connect PWB and engine PWB (YC9)
  Defective drum PWB. Replace the drum unit C.
  Defective PWB. Replace the engine PWB check for correct operation.