• Code: F2-76
• Description: Toner cartridge CRUM error (MAGENTA)
  CRUM cannot be read or written.
• Causes: Connection trouble or disconnection of the connector and the harness between the PCU and the toner cartridge. CRUM trouble Control PWB (PCU) trouble
• Remedy: Case 1 Cause Connection trouble or disconnection of the connector and the harness between the PCU and the toner cartridge. Check and remedy Check the connector and the harness between the PCU and the toner cartridge. Case 2 Cause CRUM trouble Check and remedy Replace the toner cartridge. Case 3 Cause Control PWB (PCU) trouble Check and remedy Replace the PCU PWB.

• Code: F2-77
• Description: Toner cartridge CRUM error (YELLOW)
  CRUM cannot be read or written.
• Causes: Connection trouble or disconnection of the connector and the harness between the PCU and the toner cartridge CRUM trouble Control PWB (PCU) trouble
• Remedy: Case 1 Cause Connection trouble or disconnection of the connector and the harness between the PCU and the toner cartridge. Check and remedy Check the connector and the harness between the PCU and the toner cartridge. Case 2 Cause CRUM trouble Check and remedy Replace the toner cartridge. Case 3 Cause Control PWB (PCU) trouble Check and remedy Replace the PCU PWB.

• Code: F2-78
• Description: Registration exclusive image density sensor trouble (Transfer belt surface reflection ratio abnormality)
  The transfer belt surface is scanned by the image density sensor before starting the registration, and adjust the sensor gain so that the output is kept at a certain level. However, the output is not within the specified range though the senor gain is adjusted.
• Causes: Image density sensor trouble, harness connection trouble between PCU PWB and the image density sensor, image density sensor dirt, transfer belt cleaning trouble, calibration plate solenoid operation trouble
• Remedy: Check the sensor and the harness. Check the calibration plate solenoid operation and the transfer belt surface state. If the trouble is not cleared, replace the image sensor exclusively used for registration, replace the transfer belt, replace the calibration plate, replace the solenoid, or replace the PCU PWB according to the check result.

• Code: F2-80
• Description: Half tone process control 1st patch reference value trouble (BLACK)
  The low-density rising point or the high-density saturation point cannot be calculated because of a calculation error in the primary approximation formula of the sensor output ratio for the LSU PWM value obtained from the first step patch print result when executing the half tone process control in BLACK.
• Causes: Image density sensor trouble, harness connection trouble between PCU sub PWB and the image density sensor, image density sensor dirt, transfer belt cleaning trouble
• Remedy: Use SIM44-2 to execute the process control gain adjustment. If "ERROR" is displayed, check the sensor and the harness. If the adjustment is completed, check the drum surface state and the belt surface state.

• Code: F2-81
• Description: Half tone process control 1st patch reference value trouble (CYAN)
  The low-density rising point or the high-density saturation point cannot be calculated because of a calculation error in the primary approximation formula of the sensor output ratio for the LSU PWM value obtained from the first step patch print result when executing the half tone process control in CYAN.
• Causes: Image density sensor trouble, harness connection trouble between PCU sub PWB and the image density sensor, image density sensor dirt, transfer belt cleaning trouble
• Remedy: Use SIM44-2 to execute the process control gain adjustment. If "ERROR" is displayed, check the sensor and the harness. If the adjustment is completed, check the drum surface state and the belt surface state.

• Code: F2-82
• Description: Half tone process control 1st patch reference value trouble (MAGENTA)
  The low-density rising point or the high-density saturation point cannot be calculated because of a calculation error in the primary approximation formula of the sensor output ratio for the LSU PWM value obtained from the first step patch print result when executing the half tone process control in MAGENTA.
• Causes: Image density sensor trouble, harness connection trouble between PCU sub PWB and the image density sensor, image density sensor dirt, transfer belt cleaning trouble
• Remedy: Use SIM44-2 to execute the process control gain adjustment. If "ERROR" is displayed, check the sensor and the harness. If the adjustment is completed, check the drum surface state and the belt surface state.

• Code: F2-83
• Description: Half tone process control 1st patch reference value trouble (YELLOW)
  The low-density rising point or the high-density saturation point cannot be calculated because of a calculation error in the primary approximation formula of the sensor output ratio for the LSU PWM value obtained from the first step patch print result when executing the half tone process control in YELLOW.
• Causes: Image density sensor trouble, harness connection trouble between PCU sub PWB and the image density sensor, image density sensor dirt, transfer belt cleaning trouble
• Remedy: Use SIM44-2 to execute the process control gain adjustment. If "ERROR" is displayed, check the sensor and the harness. If the adjustment is completed, check the drum surface state and the belt surface state.

• Code: F2-84
• Description: Half tone process control 2nd patch reference value trouble (BLACK)
  The low-density section output is greater than the middle-density section output when connecting the low-density section approximation formula and the middle-density section approximation formula (formula of the sensor output ratio for the LSU PWM value) from the second step patch print result when executing the half tone process control in BLACK.
• Causes: Image density sensor trouble, harness connection trouble between PCU sub PWB and the image density sensor, image density sensor dirt, transfer belt cleaning trouble, transfer belt cleaning trouble
• Remedy: Use SIM44-2 to execute the process control gain adjustment. If "ERROR" is displayed, check the sensor and the harness. If the adjustment is completed, check the drum surface state and the belt surface state.