• Code: 7904
• Description: Drum unit EEPROM error (Yellow) No response is issued from the device in reading/ writing for 5 ms or more and this problem is repeated 5 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: Drum unit 1. Unplug the power cord from the wall outlet, and wait five seconds. Then plug in the power cord and then turn on the power switch. 2. Confirm that the connector of the drum unit is firmly connected, and if necessary, push the unit all the way in. 3. Confirm that the wiring connector is firmly connected, and if necessary, connect the connector all the way in. Drum unit - Unit relay PWB Unit relay PWB - Main/Engine PWB(YC7) 4. If the wire is disconnected, short-circuited or has a ground fault, or the connector pin is deformed, replace the wire. 5. Replace the drum unit.
  Unit relay PWB Replace the unit relay PWB.
  Main/Engine PWB 1. Check the engine firmware and upgrade to the latest version if necessary. 2. Replace the main/engine PWB.

• Code: 7911
• Description: Developer unit EEPROM error (Black) No response is issued from the device in reading/ writing for 5 ms or more and this problem is repeated 5 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: Developer unit 1. Unplug the power cord from the wall outlet, and wait five seconds. Then plug in the power cord and then turn on the power switch. 2. Confirm that the connector of the developer unit is firmly connected, and if necessary, push the unit all the way in. 3. Confirm that the wiring connector is firmly connected, and if necessary, connect the connector all the way in. Developer unit - Unit relay PWB Unit relay PWB - Main/Engine PWB(YC7) 4. If the wire is disconnected, short-circuited or has a ground fault, or the connector pin is deformed, replace the wire. 5. Replace the developer unit.
  Unit relay PWB Replace the unit relay PWB.
  Main/Engine PWB 1. Check the engine firmware and upgrade to the latest version if necessary. 2. Replace the main/engine PWB.

• Code: 7912
• Description: Developer unit EEPROM error (Cyan) No response is issued from the device in reading/ writing for 5 ms or more and this problem is repeated 5 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: Developer unit 1. Unplug the power cord from the wall outlet, and wait five seconds. Then plug in the power cord and then turn on the power switch. 2. Confirm that the connector of the developer unit is firmly connected, and if necessary, push the unit all the way in. 3. Confirm that the wiring connector is firmly connected, and if necessary, connect the connector all the way in. Developer unit - Unit relay PWB Unit relay PWB - Main/Engine PWB(YC7) 4. If the wire is disconnected, short-circuited or has a ground fault, or the connector pin is deformed, replace the wire. 5. Replace the developer unit.
  Unit relay PWB Replace the unit relay PWB.
  Main/Engine PWB 1. Check the engine firmware and upgrade to the latest version if necessary. 2. Replace the main/engine PWB.

• Code: 7913
• Description: Developer unit EEPROM error (Magenta) No response is issued from the device in reading/ writing for 5 ms or more and this problem is repeated 5 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: Developer unit 1. Unplug the power cord from the wall outlet, and wait five seconds. Then plug in the power cord and then turn on the power switch. 2. Confirm that the connector of the developer unit is firmly connected, and if necessary, push the unit all the way in. 3. Confirm that the wiring connector is firmly connected, and if necessary, connect the connector all the way in. Developer unit - Unit relay PWB Unit relay PWB - Main/Engine PWB(YC7) 4. If the wire is disconnected, short-circuited or has a ground fault, or the connector pin is deformed, replace the wire. 5. Replace the developer unit.
  Unit relay PWB Replace the unit relay PWB.
  Main/Engine PWB 1. Check the engine firmware and upgrade to the latest version if necessary. 2. Replace the main/engine PWB.

• Code: 7914
• Description: EEPROM error (Yellow) No response is issued from the device in reading/ writing for 5 ms or more and this problem is repeated 5 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: Developer unit 1. Unplug the power cord from the wall outlet, and wait five seconds. Then plug in the power cord and then turn on the power switch. 2. Confirm that the connector of the developer unit is firmly connected, and if necessary, push the unit all the way in. 3. Confirm that the wiring connector is firmly connected, and if necessary, connect the connector all the way in. Developer unit - Unit relay PWB Unit relay PWB - Main/Engine PWB(YC7) 4. If the wire is disconnected, short-circuited or has a ground fault, or the connector pin is deformed, replace the wire. 5. Replace the developer unit.
  Unit relay PWB Replace the unit relay PWB.
  Main/Engine PWB 1. Check the engine firmware and upgrade to the latest version if necessary. 2. Replace the main/engine PWB.

• Code: 9540
• Description: Backup data error The internal data changes by replacing multiple parts at the same time, interfering with the machine operation and will not enter ready mode.
• Remedy: PWBs In case two or more of the parts below were replaced at the same time, reattach them. Applicable parts: Memory, PWBs *When replacing the applicable parts, 2 or more do not replace then at the same time. *When replacing the above applicable parts, do not work the following at the same time. Replace the drum unit or the developing unit. Replace the drum unit for one color with another in the same machine.

• Code: F000
• Description: Communication error between Main/Engine PWB - Operation panel PWB
• Remedy: Main/Engine PWB 1. Unplug the power cord from the wall outlet, and wait five seconds. Then plug in the power cord and then turn on the power switch. 2. Check the wiring and connectors between the main/engine PWB - the operation panel PWB. Operation panel PWB - Main/Engine PWB (YC26) : M21 ppm model - Main/Engine PWB (YC56) : M26 ppm model 3. Check the connection of the DDR memory on the main/engine PWB by reinstalling it or replacing it. 4. Replace the main/engine PWB.
  Operation panel PWB Replace the operation panel PWB.

• Code: F000
• Description: CF000 will be displayed if * notes progress is carried out for a definite period of time with a Welcome screen.The communication fault between Panel-Main boardsCommunication fault between Panel Core-Main Core Notes 2
• Remedy: (1) Check the harness of * (between Main board <=>HDD), and the connection state of a connector between Panel<=>Main boards, and perform an operation check. (2) Check contact of a DDR memory (extracting) and perform an operation check. If exchangeable, it will exchange and will perform an operation check. (3) Initialize HDD and perform an operation check. (FULL of U024) * ( 4) U021 Controller backup initialization is carried out and an operation check is performed. (5) Exchange a Main board and perform an operation check. (6) Exchange a PanelMain board and perform an operation check. (7) It will get, if USBLOG is obtainable, and contact service headquarters. * : only HDD standard model * Note 2 : Only Dual Core CPU model