Brother FAX4750 Service Manual page 188

[ 5 ] Print-image related
If the received or sent image has any problem, first make a copy with the facsimile equipment.
If the copied image is normal, the problem may be due to the remote terminal; if it is abnormal,
proceed to the following checks:
Trouble
(1) Completely blank
(2) All black
At the scanner
Check the following components:
- CIS harness
- Main PCB
- CIS unit
At the printer side
Clean the high-voltage contacts for the developer roller on
l
the drum unit, main cover, and high-voltage power supply
ƒ
PCB. (Contacts
Clean the grounding contacts on the drum unit, main cover,
l
and high-voltage power supply PCB. (Contacts
illustration given on page VI-27)
Replace the toner cartridge.
l
Replace the drum unit.
l
Check the connection of the laser flat cable on the main
l
PCB.
Replace the main PCB.
l
Replace the laser unit.
l
Replace the high-voltage power supply PCB.
l
At the scanner
Check the following components:
- CIS harness
- CIS unit
- Main PCB
At the printer side
Clean the high-voltage contacts for the grid and charger on
l
the drum unit, main cover, and high-voltage power supply
„
PCB. (Contacts
VI-27)
Clean the charger (corona wires) itself.
l
Check the connection of the laser flat cable on the main
l
PCB.
Replace the drum unit.
l
Replace the high-voltage power supply PCB.
l
Replace the main PCB.
l
VI - 20
Action to be taken
in the illustration given on page VI-27)
‚
and in the illustration given on page
•
in the