Others Problems - Brother HL-4040CN Service Manual

7.

OTHERS PROBLEMS

The machine is not turned on, or the LCD indication does not appear.
Step
1
Harness
connection failure
of LCD panel
PCB
2 LCD panel PCB
failure
3
LCD panel failure
4
Low-voltage
power supply
failure
5
Main PCB failure
The fan does not work.
(Verify the position of each fan referring to
78)" in Chapter
Step
1
Harness
connection failure
of the appropriate
fan
2
Charge HVPS
PCB failure
3
Low-voltage
power supply
failure
4
Engine PCB
failure
5
Main PCB failure
Cause
Is the harness of the LCD
panel PCB ASSY
connected correctly?
Is the problem solved
after replacing the LCD
panel PCB ASSY?
Is the problem solved
after replacing the LCD
panel ASSY?
Is the problem solved
after replacing the PS
PCB unit?
Is the problem solved
after replacing the main
PCB ASSY?
5.)
Cause
Is the harness of the
appropriate fan connected
correctly?
Is the problem solved
after replacing the charge
HVPS PCB ASSY?
Is the problem solved
after replacing the PS
PCB unit?
Is the problem solved
after replacing the engine
PCB ASSY?
Is the problem solved
after replacing the main
PCB ASSY?
Check
Result
No
Yes
Yes
Yes
Yes
"1.4.16 Operational Check of Fans (Function code
Check
Result
No
Yes
Yes
Yes
Yes
1-59
Remedy
Reconnect the LCD
panel PCB ASSY
harness
Replace the LCD panel
PCB ASSY.
Replace the LCD panel
ASSY.
Replace the PS PCB unit.
Replace the main PCB
ASSY.
Remedy
Reconnect the harness of
the appropriate fan
correctly.
Replace the charge
HVPS PCB ASSY.
Replace the fuser unit fan
(FU) and air intake fan
(AIR).
Replace the PS PCB unit.
Replace the LVPS fan
(PS).
Replace the engine PCB
ASSY. Replace the drum
unit fan (OPC).
Replace the main PCB
ASSY.
Confidential