• Code: E405
• Description: Abnormally high toner density detected Yellow TCR Sensor
  - Mixture ratio of the toner and carrier in the developing machine is higher than the specified value.
• Causes: • Photoconductor Unit/C • Photoconductor Unit/M • Photoconductor Unit/Y • Mechanical Control Board (PWB-M) • Controller Board (PWB-P)
• Remedy: 1 Clean the TCR Sensor window on the underside of the Photoconductor Unit if dirty. - - 2 Reinstall Photoconductor Unit. - - 3 Change Photoconductor Unit. - - 4 Change PWB-M - - 5 Change PWB-P

• Code: E406
• Description: Abnormally low toner density detected Black TCR Sensor
  - Mixture ratio of the toner and carrier in the developing machine is lower than the specified value.
• Causes: • Photoconductor Unit /K • Toner Supply Motor C/K (M7) • Mechanical Control Board (PWB-M) • Controller Board (PWB-P)
• Remedy: 1 Perform image troubleshooting procedure if image density is low. - - 2 Clean the TCR Sensor window on the underside of the Photoconductor Unit if dirty. - - 3 M7 operation check PWB-M CNDM3-10 to 13 C-23 4 Reinstall Photoconductor Unit - - 5 Change Photoconductor Unit /K - - 6 Change PWB-M - - 7 Change PWB-P

• Code: E407
• Description: Abnormally high toner density detected Black TCR Sensor
  - Mixture ratio of the toner and carrier in the developing machine is higher than the specified value.
• Causes: • Photoconductor Unit /K • Mechanical Control Board (PWB-M) • Controller Board (PWB-P)
• Remedy: 1 Clean the TCR Sensor window on the underside of the Photoconductor Unit if dirty. - - 2 Reinstall Photoconductor Unit - - 3 Change Photoconductor Unit /K - - 4 Change PWB-M - - 5 Change PWB-P

• Code: E500
• Description: Main Motor's failure to turn
  - The Motor Lock signal remains HIGH for a predetermined continuous period of time while the Motor is turning.
• Causes: • Main Motor (M1) • Mechanical Control Board (PWB-M) • DC Power Supply (PU1)
• Remedy: 1 Check the M1 connector for proper connection and correct as necessary. - - 2 Check M1 for proper drive coupling and correct as necessary. - - 3 Check the PWB-M connector for proper connection and correct as necessary. - - 4 M1 operation check PWB-M CNDM1-5 (REM) PWB-M CNDM1-8 (LOCK) K ` L-2 5 Change PWB-M - - 6 Change PU1

• Code: E501
• Description: Main Motor turning at abnormal timing
  - The Motor Lock signal remains LOW for a predetermined continuous period of time while the Motor remains stationary
• Causes: • Main Motor (M1) • Mechanical Control Board (PWB-M) • DC Power Supply (PU1)
• Remedy: 1 M1 operation check PWB-M CNDM1-5 (REM) PWB-M CNDM1-8 (LOCK) K to L-2 2 Change PWB-M - - 3 Change PU1

• Code: E510
• Description: Color PC Drum Motor's failure to turn
  - The Motor Lock signal remains HIGH for a predetermined continuous period of time while the Motor is turning.
• Causes: • Color PC Drum Motor (M2) • Mechanical Control Board (PWB-M)
• Remedy: 1 Check the connector of motor for proper connection and correct as necessary. - - 2 Check the connector of motor for proper drive coupling and correct as necessary. - - 3 Check the PWB-M connector for proper connection and correct as necessary. - - 4 M2 operation check PWB-M CNDM3-5 (REM) PWB-M CNDM3-8 (LOCK) C-23 5 Change PWB-M

• Code: E511
• Description: Color PC Drum Motor's turning at abnormal timing
  - The Motor Lock signal remains LOW for a predetermined continuous period of time while the Motor remains
  stationary.
• Causes: • Color PC Drum Motor (M2) • Mechanical Control Board (PWB-M)
• Remedy: 1 M2 operation check PWB-M CNDM3-5 (REM) PWB-M CNDM3-8 (LOCK) C-23 2 Change PWB-M

• Code: E520
• Description: Color Developing Motor's failure to turn
  - The Motor Lock signal remains HIGH for a predetermined continuous period of time while the Motor is turning.
• Causes: • Color Developing Motor (M3) • DC Power Supply (PU1) • Mechanical Control Board (PWB-M)
• Remedy: 1 Check the connector of motor for proper connection and correct as necessary. - - 2 Check the connector of motor for proper connection and correct as necessary. - - 3 Check the PU1 connector for proper connection and correct as necessary. - - 4 Check the PWB-M connector for proper connection and correct as necessary. - - 5 M3 operation check PWB-M CNDM2-5 (REM) PWB-M CNDM2-8 (LOCK) C-22 6 Change PU1 - - 7 Change PWB-M