Brother MFC-P2000 - B/W Laser Printer Service Manual page 77

I-3 Completely blank
<Scanning>
Possible cause Step
CIS harness
connection
CIS unit failure
Sensor harness
connection
Main PCB
failure
<Printing>
Possible cause Step
Developing bias
contact failure
Drum unit
Drum unit failure
Scanner harness
connection failure
Main / Panel
sensor PCB
connection failure
Laser unit failure
Check
1 Is the CIS harness connected
securely?
2
Is the problem solved after the
CIS unit is replaced?
3 Is the sensor harness
connected between the main
PCB and the scanner sensor
PCB securely?
4 Is the problem solved after the
main PCB is replaced?
Check
1 Are the developing bias
contacts between the printer
body and drum unit dirty?
2 Are the drum shaft and drum
electrode of the printer body
connected correctly?
3 Is the problem solved after the
drum unit is replaced?
4 Is the scanner harness
connected securely?
Is there any play in the
connection?
5 Are printing signals being input
to the scanner?
Is the problem solved after the
main PCB or the panel sensor
PCB replaced?
6 Laser interlock lever damaged.
Laser mirror is broken or loose.
Result
No
Yes
No
Yes
Result
Yes
Yes
No
Yes
No
Yes
Yes
No
IV-8
Remedy
Reconnect the CIS harness.
Replace the CIS unit.
Reconnect the sensor harness.
Replace the main PCB.
Remedy
Clean the electrodes
at both sides.
Clean the shaft and
the electrode.
Check the connection
between the shaft and
the electrode.
Replace the drum
unit.
Reconnect the
connector properly.
Replace the main
PCB or the panel
sensor PCB.
Replace the laser
unit.
Replace the high-
voltage power supply
PCB.
GND
contacts
(Fig.4-5)