Brother MFC-P2000 - B/W Laser Printer Service Manual page 75

I-1 Light
<Scanning >
Possible cause Step
Main PCB
failure
Laser unit failure
<Printing>
Possible cause Step
Toner sensing
failure
(printer side)
Toner sensing
failure
(toner cartridge
side)
Drum
connection
failure
High-voltage
power supply
PCB failure
Panel sensor
PCB or main
PCB failure
Laser unit failure
Check
1 Is the problem solved after the
main PCB is replaced?
2 Is the problem solved after the
laser unit is replaced?
Check
1 Can printing be started with the
drum unit removed?
2 Is the problem solved when 4
or 5 pages are printed after the
toner cartridge is replaced with
a full one?
3 Are all the contacts (HV, GND)
connected when the drum unit
is installed?
4 Check the harness connection
between the high-voltage
power supply PCB and the
panel sensor PCB.
5 Perform the same check as
step 4 above and also between
the panel sensor PCB and the
main PCB.
6 Is the problem solved by
replacing the laser unit?
Result
Yes
Yes
Result
Yes
Yes
No
No
No
Yes
IV-6
Remedy
Replace the main PCB.
Replace the laser unit.
Remedy
Toner sensor failure.
Check if the toner
sensor needs
cleaning and check
the toner sensor
connection.
The wiper of the
toner cartridge is
defective, or replace
the toner cartridge.
Clean contact
electrodes both in the
printer body and on
the drum unit.
If the connection is
normal, replace the
high-voltage power
supply PCB.
Replace the panel
sensor PCB or the
main PCB.
Replace the laser
unit.
GND
contacts
(Fig.4-5)