Brother HL-4000CN, Service Manual

Page: 285 / 345

V-75
11.3 Toubleshooting Table by Trouble Phenomena
<Fogging>
Fig.5-17
Condition:
Fogging over print. Toner attaches to margin of print.
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