Brother 1240 Service Manual page 154

CHAPTER 6 TROUBLESHOOTING
I-11
Possible cause
Excessive paper
load
Print paper
Rear resist
sensor position
incorrect
I-12 Poor fixing
Possible cause
Print paper
Toner sensing
failure
(When printing
is faint.)
Thermistor
failure
Low-voltage
power supply
PCB failure
Faulty registration
Step
1 Is the paper loaded in the
paper cassette more than
27mm high?
2 Is the specified weight of the
recommended paper being
used?
3 Is the first printing position
within ±1mm of the tolerance
specification?
4 Is the position of the rear
registration sensor normal?
Step
1 Is thick paper of more than
43lb being used?
2 Is the problem solved by
replacing the drum unit or the
toner cartridge?
3 Is the thermistor fitted
correctly?
4 Is the problem solved by
replacing the low-voltage
power supply PCB?
Check Result
Check Result
6-32
Remedy
Yes Instruct the user to keep paper
loads below 27mm in depth.
No Recommend to use the specified
types of paper.
Yes Adjust the Y offset by using the
utility software supplied.
No Reposition the sensor to the
correct position.
Remedy
Yes Recommend to use the specified
types of paper.
Yes 1) Toner is empty.
2) The toner sensing is
defective. Clean the toner
sensor.
3) If the wiper in the toner
cartridge is broken, replace
the toner cartridge with a new
one.
No Fit the thermistor correctly.
Yes Replace the low-voltage power
supply PCB.