• Code: 621
• Description: Finisher communication error
  While the IOB communicates with an optional unit, an SC code is displayed if one of following conditions occurs. • The IOB receives the break signal which is generated by the peripherals only just after the main switch is turned on. • When the IOB does not receive an OK signal from a peripheral 100ms after sending a command to it. And when the IOB does not receive an OK signal even after sending the command 3 times, the IOB resends the command.
• Causes: • Cable problems • IOB problems • EGB problems • PSU problems in the machine • Main board problems in the peripherals
• Remedy: 1. Check if the cables of peripherals are correctly connected. 2. Replace the PSU if no power is supplied to peripherals. 3. Replace the IOB or main board of peripherals. 4. Replace the EGB.

• Code: 622
• Description: Paper tray unit communication error
  While the IOB communicates with an optional unit, an SC code is displayed if one of following conditions occurs. • The IOB receives the break signal which is generated by the peripherals only just after the main switch is turned on. • When the IOB does not receive an OK signal from a peripheral 100ms after sending a command to it. And when the IOB does not receive an OK signal even after sending the command 3 times, the IOB resends the command.
• Causes: • Cable problems • IOB problems • EGB problems • PSU problems in the machine • Main board problems in the peripherals
• Remedy: 1. Check if the cables of peripherals are correctly connected. 2. Replace the PSU if no power is supplied to peripherals. 3. Replace the IOB or main board of peripherals. 4. Replace the EGB.

• Code: 623
• Description: Optional paper feed unit communication error
  In the case of installing two optional paper feed units (G832 + B800, G832 + B801, or G832 + G832): • The upper unit cannot communicate with the lower unit after the upper unit has detected the lower unit. • The upper unit detects an error signal from the lower unit after the upper unit has detected the lower unit.
• Causes: • Disconnected connector
• Remedy: Check and/ or connect the connector.

• Code: 669
• Description: EEPROM error
  Retry of EEPROM communication fails three times after the machine has detected the EEPROM error
• Causes: • Caused by noise
• Remedy: Turn the main power switch off and on.

• Code: 670
• Description: No response from controller at power on
  When the main power is turned on or the machine starts warming up from energysaving mode, the controller does not receive a command signal from the controller
• Causes: • Loose connection • Defective controller • Defective controller board
• Remedy: 1. Check the connection between the EGB and controller. 2. Replace the controller. 3. Replace the EGB.

• Code: 681
• Description: RFID: Communication error
  • Communication error occurs when the RFID starts to communicate with the RFID receptor. • Retry of RFID communication fails three times after the machine has detected the RFID communication error.
• Causes: • Defective RFID reader and writer • Disconnected ASAP I/F • No memory chip on the toner cartridge • Noise
• Remedy: 1. Replace the RFID controller board. 2. Replace the toner cartridge.

• Code: 682
• Description: Memory chip at TD sensor: Communication error
  Retry of memory chip communication fails three times after the machine has detected the memory chip communication error.
• Causes: • Damaged memory chip data • Disconnected inter face • No memory chip on the development unit • Noise
• Remedy: Replace the PCU.

• Code: 683
• Description: RFID: Unit check error
  The machine gets RFID communication error even the toner cartridges have not been installed in the machine
• Causes: Caused by noise
• Remedy: Turn the main power switch off and on.