Brother mfc8440 - Page 231

CHAPTER 6 TROUBLESHOOTING
6-24
WARNING
If you analyze malfunctions with the power plug inserted into the power outlet, special
caution should be exercised even if the power switch is OFF because it is a single pole
switch.
M-3 Main motor failure
Possible cause Step Check Result Remedy
Failure of
connector
1 Is the connection of connector
CN9 on the engine PCB
correct?
No Reconnect the connector.
Main motor 2 Is the problem solved by
replacing the main motor?
Yes Replace the main motor.
Engine PCB 3 Is the problem solved by
replacing the engine PCB?
Yes Replace the engine PCB.
Main PCB 4 Is the problem solved by
replacing the main PCB?
Yes Replace the main PCB.
M-4 No paper supplied
Possible cause Step Check Result Remedy
Failure of
connector
1 Is the contact of the solenoid
connector on the engine PCB
good?
No Reconnect the connector.
Engine PCB
circuit
2 Set paper in the manual paper
slot and make a test print by
pressing the control panel
button.
Yes Replace the engine PCB.
Paper pick-up
clutch solenoid
Does the voltage between pins
2 (SOLENOID) and 1 (24V) of
the CN16 connector on the
engine PCB change from
approx. 24V DC to 0V within
the specified time?
No Replace the paper pick-up
solenoid.
Separation pad /
pick-up roller
failure
3 Is the surface of the separation
pad or the pick-up roller dirty or
worn out?
Yes 1) Clean the surface of the
separation pad or pick-up
roller.
2) Replace the separation
pad or pick-up roller.
Main PCB 4 Is the problem solved by
replacing the main PCB?
Yes Replace the main PCB.