Brother HL-4000CN - Page 287

V-77
<Streak in the shaft direction>
Fig.5-20 Fig.5-21
Condition:
Black or white streaks in the shaft direction.
Initial check:
Parts of different specifications, improper installation, damage, deformation, dirt, foreign
substance attached, etc.
Major parts to be checked:
Print head cartridge ASSY, Fuser ASSY, Transfer roll cartridge ASSY, Scanner ASSY,
MCU and HVPS PWB, SUB HVPS
Item Check Remedy
1
Faulty print head cartridge ASSY
Is the image quality improved if print head cartridge
ASSY is replaced?
Replace the print head
cartridge ASSY
2
Faulty scanner ASSY
Is the image quality improved if scanner ASSY is
replaced?
Replace the scanner
ASSY
3
Faulty fuser ASSY
Check the heat roll and NIP belt for evidence of
damage, dirt, or foreign substances.
Replace the fuser ASSY
4
Faulty transfer roll cartridge ASSY
Is the image quality improved if transfer roll
cartridge ASSY is replaced?
Replace the transfer roll
cartridge ASSY
5
Check periodicity
Periodicity found？
Replace the parts
concerned.
（See the table below）
6
Faulty ESS PWB
Is the image quality improved if ESS PWB is
replaced?
Replace the ESS PWB