Brother MFC640CW Service Manual page 258

Error Code
(Hex)
48 Weak connection of the
head flat cables.
49 The head drive voltage has
not risen to the specified
level.
4A-4E Not used.
4F The head drive voltage has
dropped from the high to
low level in an abnormally
short period.
50 The purge cam switch
51 does not come ON or OFF
even after the purge cam
has been driven by the
specified number of
pulses.
The purge cam switch
52
does not come ON at each
detection point.
Symptom
9- 7
Probable Cause
Head flat cables or
carriage-head flat cable
broken or not
connected
Head flat cables and
carriage-head flat cable
not connected correctly
Main PCB defective
Power supply PCB
defective
Piezoelectric (PZT)
ceramic actuator
defective (Cracks or
rare short)
Switching arm
assembly not engaged
correctly
Ink cartridge/purge
switch harness not
connected correctly
Purge cam switch
broken
Gear(s) on the
maintenance unit
broken
Paper feed motor
broken
Main PCB defective.
Switching arm
assembly not engaged
correctly
Gear(s) on the
maintenance unit
broken
Abnormal load applied
to the purge cam
Paper feed motor
broken
Main PCB defective
Solution
Replace those cables or
correct their connection.
Correct those flat
cables.
Replace the main PCB.
Replace the power
supply PCB.
Replace the
head/carriage unit.
Replace the power
supply PCB.
Replace the main PCB.
If the switching arm does
not move smoothly,
clean it.
Correct the connection.
Replace the purge cam
switch.
Replace the maintenance
unit.
Replace the paper feed
motor.
Replace the main PCB.
If the switching arm does
not move smoothly,
clean it.
Replace the maintenance
unit.
Replace the paper feed
motor.
Replace the main PCB.
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