• Code: 7401
• Description: Developer unit type mismatch error
  Improper adaptation of the machine and developer unit is detected.
• Causes: Different type of the developer unit is installed. Developer unit.
• Remedy: Different type of the developer unit is installed. Install the developer unit of the correct type.
  Developer unit 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Developer unit and Front PWB (YC7) Front PWB (YC2) and Engine PWB (YC8) 2. If the wiring is disconnected, shorted or grounded, replace the wiring.

• Code: 7460
• Description: Developer shutter error
  Power is turned on while the developer shutter is locked.
• Causes: The developer shutter has been locked. Developer shutter sensor.
• Remedy: The developer shutter has been locked. Release the developer shutter.
  Developer shutter sensor 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Developer shutter sensor and Front PWB (YC4) Front PWB (YC3) and Engine PWB (YC7) 2. If the wiring is disconnected, shorted or grounded, replace the wiring.

• Code: 7601
• Description: ID sensor 1 error [Front]
  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].
• Causes: ID sensor1. Feed PWB 1. Engine PWB.
• Remedy: ID sensor1 1. Execute U464 Calib for setting ID compensation operation and check the displayed values by U465 Boas Calib for ID compensation reference. 2. 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 relay PWB (YC10) Relay PWB (YC1) and Feed PWB 1 (YC14) 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 [Rear]
  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].
• Causes: ID sensor 2. Feed PWB 1. Engine PWB.
• Remedy: ID sensor 2 1. Execute U464 Calib for setting ID compensation operation and check the displayed values by U465 Boas Calib for ID compensation reference. 2. 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 relay PWB (YC10) Relay PWB (YC1) and Feed PWB 1 (YC14) 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 wire
  The device did not respond for more than 5 ms during reading, in 5 times.
• Causes: Outer temperature sensors been locked. Front PWB. Engine PWB.
• Remedy: Outer temperature sensor 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Outer temperature sensor and Front PWB (YC8) Front PWB (YC2) and Engine PWB (YC8) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the Outer temperature sensor.
  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 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.
• Causes: DR PWB. Front PWB. Engine PWB.
• Remedy: DR PWB 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. DR PWB and Front PWB (YC6) Front PWB (YC2) and Engine PWB (YC8) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the Drum unit.
  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: 7911
• Description: Developer unit 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.
• Causes: Developer unit. Front PWB. Engine PWB.
• Remedy: Developer unit 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Developer unit and Front PWB (YC7) Front PWB (YC2) and Engine PWB (YC8) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the Developer unit.
  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: 7941
• Description: Laser scanner unit EEPROM error
  Mismatch of reading data from two locations occurs 8 times successively. Mismatch between writing data and reading data occurs 8 times successively.
• Causes: APC PWB. LSU relay PWB. Engine PWB.
• Remedy: APC PWB 1. Confirm that the FCC wiring connector is not distorted and connect the FCC wiring all the way in. APC PWB and LSU relay PWB (YC3) LSU relay PWB (YC2) and Engine PWB (YC11) 2. If the FCC wiring is disconnected, shorted or grounded, replace the FCC wiring. 3. Replace the laser scanner unit.
  LSU relay PWB Replace the LSU relay PWB.
  Engine PWB 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB.