• Code: 7251
• Description: Short-circuited developer thermistor The sensor input sampling is less than 69.
• Remedy: Developer thermistor 1. Confirm Developing is displayed by U139 temperature and humidity. 2. 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) 3. If the wiring is disconnected, shorted or grounded, replace the wiring. 4. 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: 7301
• Description: Toner hopper motor error During the Toner hopper motor is driven, an event in which a locking was detected for 5 times in 200 ms intervals has occurred in 30 sets.
• Remedy: Toner hopper motor 1. If the motor won’t rotate, confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Toner hopper motor and Front PWB (YC5) Front PWB (YC3) and Engine PWB (YC7) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the toner hopper motor.
  Screw sensor 1. Check that the sensor is correctly positioned. 2. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Screw sensor and Front PWB (YC5) Front PWB (YC2) and Engine PWB (YC7) 3. Replace the Screw sensor.
  Engine PWB 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB.

• Code: 7401
• Description: Developer unit type mismatch error Improper adaptation of the machine and developer unit is detected.
• 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: 7411
• Description: Drum unit type mismatch error Improper adaptation of the machine and developer unit is detected.
• Remedy: Different type of the drum unit is installed. Install the drum unit of the correct type.
  Drum unit 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Drum unit and Front PWB (YC6) 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.
• 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: 7470
• Description: Failure of the fan motor that avoids internal contamination The toner fan motor signal has been detected as unconnected at power up.
• Remedy: Toner disposal box 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Toner disposal box and Feed PWB 1 (YC14) Feed PWB 1 (YC1) and Engine PWB (YC6) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the Toner disposal box.
  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: 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].
• 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].
• 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.