Xerox WorkCentre Pro 423 Service Manual page 256

WorkCentre Pro 423/428
Cause Corrective action
• Check NVM setup data. [21-37]
Inappropriate AE setup data
• Check NVM setup data. [21-56][21-57]
Inappropriate shading
compensation coefficient
• Print out built-in Test Pattern (continuous
Control Board
• Faulty MCU/SW PWB or
IIT/IPS PWB
• Check that the connections are secure.
Control Board
• Connection failure of MCU/SW
PWB, IIT/IPS PWB, MF MAIN
PWB
• Replace CCD PWB.
Control Board
• Faulty CCD PWB
• Check NVM setup data.
Density setup failure
gradation) to check and isolate faulty board.
(Diag [21-5 to 57])
3-12 CHAPTER 3 IMAGE QUALITY TROUBLESHOOTING
C - 2 White copies
Copy sample
Symptom
White copies
(Output of entirely white copies without characters and drawings)
Cause
Drum
• Drum revolution failure
Drum
• Quality change and
deterioration
Drum
• Magnetic roller revolution
failure
Developer bias
• Output failure of HVPS
Developer bias
• Discontinuity of magnetic roller
Interrupted laser path
Control board
• Faulty MCU/SW PWB or
IIT/IPS PWB
Control board
• Connection failure between
PWBs
Control board
• Faulty CCD PWB
Poor contact of BTR
3.3 Image Quality Troubleshooting
j0hn3005
Corrective action
• Check the CRU drive structure.
• Replace CRU.
• Check CRU and drive structure.
• Replace HVPS.
• Check continuity of magnetic roll.
• Check for foreign matter in the laser path between
ROS and drum.
• Print out built-in Test Pattern to check and isolate
faulty board.
• Check connectors for connection.
• Replace CCD PWB.
• Repair or replace BTR.