• Code: 7404
• Description: Developer unit Y type mismatch error
  Improper adaptation of the machine and developer unit Y is detected.
• Remedy: Different type of the developer unit is installed: Install the developer unit of the correct type.
  Developer unit Y: 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Developer unit Y and Front PWB (YC15) Front PWB (YC2) and Engine PWB (YC10) 2. If the wiring is disconnected, shorted or grounded, replace the wiring.

• Code: 7601
• Description: ID sensor 1 error
  An abnormal value is detected in the input data to ID sensor 1. Dark potential error FrontDarkP and FrontDarkS are greater than 0.80V. Light potential error FrontBrightS is smaller than FrontDarkS. FrontBrightP is smaller than [FrontDarkP + 0.5V].
• Remedy: ID sensor1 (front): 1. Execute U464 Calib for setting ID compensation operation and check the displayed values by U465 Boas Calib for ID compensation reference. 2. Detach the imtermediate intermediate transfer belt unit and clean the ID sensor on its surface. 3. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. ID sensor 1 (front) and Feed PWB 1(YC10) Feed PWB 1(YC1) and Engine PWB (YC6) 4. If the wiring is disconnected, shorted or grounded, replace the wiring.
  Feed PWB: 1 Replace the Feed PWB 1.
  Engine PWB: 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB.

• Code: 7602
• Description: ID sensor 2 error
  Dark potential error RearDarkP and RearDarkS are greater than 0.80V. Light potential error RearBrightS is smaller than RearDarkS. RearBrightP is smaller than [RearDarkP + 0.5V].
• Remedy: ID sensor 2 (rear): 1. Execute U464 Calib for setting ID compensation operation and check the displayed values by U465 Boas Calib for ID compensation reference. 2. Detach the imtermediate intermediate transfer belt unit and clean the ID sensor on its surface. 3. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. ID sensor2 (rear) and Feed PWB 1(YC10) Feed PWB 1(YC1) and Engine PWB (YC6) 4. If the wiring is disconnected, shorted or grounded, replace the wiring.
  Feed PWB: 1 Replace the Feed PWB 1.
  Engine PWB: 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB.

• Code: 7800
• Description: Broken outer temperature sensor 1 wire
  The device did not respond for more than 5 ms during reading, in 5 times.
• Remedy: Outer temperature sensor 1: 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Outer temperature sensor 1 and Front PWB (YC16) Front PWB (YC2) and Engine PWB (YC10) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the Outer temperature sensor 1.
  Front PWB: Replace the front PWB.
  Engine PWB: 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB

• Code: 7901
• Description: Drum 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 8 times successively. Mismatch between writing data and reading data occurs 8 times successively.
• Remedy: DR PWB-K: 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. DR PWB-K and Front PWB (YC7) Front PWB (YC2) and Engine PWB (YC10) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the Drum unit K.
  Front PWB: Replace the front PWB.
  Engine PWB 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB.

• Code: 7902
• 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 8 times successively. Mismatch between writing data and reading data occurs 8 times successively.
• Remedy: DR PWB- C: 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. DR PWB- C and Front PWB (YC12) Front PWB (YC2) and Engine PWB (YC10) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the Drum unit C.
  Front PWB: Replace the front PWB.
  Engine PWB 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB5 times.

• Code: 7903
• 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 8 times successively. Mismatch between writing data and reading data occurs 8 times successively.
• Remedy: DR PWB- M: 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. DR PWB- M and Front PWB (YC10) Front PWB (YC2) and Engine PWB (YC10) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the Drum unit M.
  Front PWB: Replace the front PWB.
  Engine PWB 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB.

• Code: 7904
• 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 8 times successively. Mismatch between writing data and reading data occurs 8 times successively.
• Remedy: DRPWB- Y: 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. DRPWB- Y and Front PWB (YC14) Front PWB (YC2) and Engine PWB (YC10) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the Drum unit Y.
  Front PWB Replace the front PWB.
  Engine PWB 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB