Xerox WorkCentre Pro 423 Service Manual page 260

WorkCentre Pro 423/428
Black lines Copy sample
C - 8
Symptom: Black lines (Black lines of below 1mm width appear on copies in the transverse
to copy feed direction)
Cause
Drum
• Flaws on Drum surface in axial
direction (At 94mm intervals)
Drum
• Drum revolution failure
Fuser
• Flaws on Heat Roller surface in axial
direction (At 94mm intervals)
Fuser
• Too high fuser temperature setting
ROS Unit
• Incident light quantity to SOS lowered
Control board
• Faulty MCU/SW PWB or IIT/IPS PWB
Control board
• Faulty CCD PWB
BCR
• Flaws on the BCR surface (in 44mm
intervals)
j0hn3011
Corrective action
• Replace CRU.
• Check CRU coupling for skipping.
• Replace Heat Roller.
• Check NVM data.
(Diag: [20-100 to 106])
• Check power source and voltage, then
replace ROS assembly.
• Print out built-in Test Pattern (continuous
gradation or 4-BIT line pattern) to check
and isolate faulty board.
• Replace CD PWB.
• Replace CRU.
3-16 CHAPTER 3 IMAGE QUALITY TROUBLESHOOTING
Black spots Copy sample
C - 9
Symptom
Black spots
(Black spots appearing on copies)
Cause
Dirty Platen Glass
Dirty Platen Cushion
Faulty BCR
Output failure of HVPS
Drum (in 94mm intervals)
• Foreign matter on Drum
surface
Drum (in 94mm intervals)
• Contamination, quality change
and deterioration of Drum
surface
Drum (in 94mm intervals)
• Spots on Drum surface
Contamination on Heat Roller
surface (in 94mm intervals)
Flaws on magnetic roll surface (in
55mm intervals)
Toner
• Flaws on Developer sleeve
3.3 Image Quality Troubleshooting
j0hn3012
Corrective action
• Clean Platen Glass.
• Clean or replace Platen Cushion.
• Replace CRU.
• Replace HVPS.
• Remove foreign matter.
• Replace CRU.
• Replace CRU.
• Clean Heat Roller.
• Replace CRU.
• Replace CRU.