Brother MFC-P2000 - B/W Laser Printer Service Manual page 78

I-4 All black
<Scanning>
Possible cause Step
CIS harness
connection
CIS unit failure
Sensor harness
connection
Main PCB
failure
<Printing>
Possible cause Step
Corona failure
Harness
connection
High-voltage
power supply
PCB
Ditto
Main PCB
Panel sensor
PCB
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 Is the corona wire of the drum
unit broken?
2 Are the electric terminal
springs in the printer body and
the electrode on the bottom
face of the drum unit dirty?
3 Is the laser unit connected with
the panel sensor PCB
correctly?
4 Is the problem solved after
high-voltage power supply
PCB replaced?
5 Perform the same check as in
step 3.
6 Is the problem solved after
main PCB is replaced?
7 Is the problem solved after the
panel sensor PCB is replaced?
Result
No
Yes
No
Yes
Result
Yes
Yes
No
Yes
Yes
Yes
Yes
IV-9
Remedy
Reconnect the CIS harness.
Replace the CIS unit.
Reconnect the sensor harness.
Replace the main PCB.
Remedy
Replace the drum
unit.
Clean the terminals
in the printer and on
the drum.
Check the harness
connection between
the laser unit and the
panel sensor PCB.
Replace the high-
voltage power supply
PCB.
Replace the panel
sensor PCB.
Replace the main
PCB.
Replace the panel
sensor PCB.
GND
contacts
(Fig.4-5)