Brother MFC-9420CN Service Manual page 264

Error Code
(Hex)
3B Black switching solenoid error
3C Transfer belt error
Transfer roller solenoid error.
3D
Transfer belt cleaning solenoid
3E
error.
Fuser unit clutch error.
3F
40 Belt marker sense error
41 HVU connection error
42 Toner empty sensor
connection error 1, 2
43
44 Lower feeder unit connection
error
Symptom
9 -8
Probable Cause
Toner cartridge
defective
Toner retract solenoid
assy defective
Engine controller board
defective
Transfer unit
defective
Marker sensor defective Replace the marker sensor
Engine controller board
defective
Transfer roller solenoid
defective
Engine controller board
defective
Transfer belt cleaning
solenoid defective
Engine controller board
defective
Fuser unit clutch
defective
Engine controller board
defective
Belt marker sensor
defective
Engine controller board
defective
LV Power Supply PCB
defective
Engine controller board
defective
Toner sensor defective
Engine controller board
defective
Lower feeder unit
connector damaged
Engine controller board
defective
Solution
Replace the toner
cartridge
Replace the toner retract
solenoid assy
Replace the engine
controller board.
Replace the transfer unit
Replace the engine
controller board.
Replace the transfer roller
solenoid
Replace the engine
controller board.
Replace the transfer belt
cleaning solenoid
Replace the engine
controller board.
Replace the fuser unit
clutch
Replace the engine
controller board.
Replace the belt marker
sensor
Replace the engine
controller board.
Replace the LV Power
Supply PCB
Replace the engine
controller board.
Replace the toner sensor
Replace the engine
controller board.
Replace the lower feeder
unit
Replace the engine
controller board.
Confidential