Brother MFC990CW Service Manual page 135

Error Code
Symptom
(Hex)
3* Head/carriage unit travel
(except 3E) error.
3E Recording error related
to ASF motor, paper
feed motor, and carriage
motor.
40 The casing internal
temperature thermistor
has detected abnormal
temperature in the
machine.
41 Not used.
42 The head drive voltage
has not dropped from the
high to low level within
the specified period.
Probable Cause
Software malfunction
Any obstacles on the travel
path of the head/carriage unit
CR timing belt come off
CR encoder strip stained or
scratched
Carriage PCB defective
Head/carriage unit broken
Carriage motor defective
Main PCB defective
Power supply PCB defective
Maintenance unit defective
ASF encoder disk, PF
encoder disk, or CR encoder
strip stained or scratched
ASF, PF, or CR encoder
defective
ASF, PF, or CR motor
defective
Main PCB defective
Main PCB defective
Casing internal temperature
thermistor defective
Piezoelectric ceramic
actuator or head driver
defective
Carriage PCB defective
Main PCB defective
4-10
Solution
Open and close the scanner
cover.
Unplug and plug the AC cord.
Clean and lubricate the CR
guide rail and CR support
chassis.
Set the CR timing belt into
place.
Replace the CR encoder strip.
Replace the carriage PCB
ASSY.
Replace the head/carriage unit.
Replace the carriage motor.
Replace the main PCB.
Replace the power supply
PCB.
Replace the maintenance unit.
Replace the ASF motor ASSY,
PF encoder disk, or CR
encoder strip.
Replace the ASF motor ASSY,
PF encoder PCB, or carriage
PCB.
Check the ASF motor, paper
feed motor, and carriage
motor, then replace the
defective one(s).
Replace the main PCB.
Replace the main PCB.
Replace the ink refill ASSY.
Replace the head/carriage unit.
Replace the carriage PCB
ASSY.
Replace the main PCB.
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