Brother MFC-9420CN Service Manual page 262

Error Code
(Hex)
28 Charge HV unit error
29 LVPS error.
2A Fuser thermistor error
Fuser heater error.
2B
Fuser temperature low error at
2C
warming-up.
Fuser temperature low error
2D
Fuser temperature high error
2E
Fuser ACOFF error.
2F
Erase LED error
30
Power supply fan error
31
Exit fan error
32
Laser unit fan ASSY error
33
Symptom
9 -6
Probable Cause
HV Power Supply
defective
LV Power Supply
defective
thermistor
Fuser
defective
Engine controller board
defective
Breakdown of Heater
On/Off Circuit
Breakdown of Temp
Control Circuit
Contact Failure of
Harness Connector
Low Input Voltage
Low Input Voltage
Breakdown of Heater
On/Off Circuit
Breakdown of Temp
Control Circuit
Breakdown of Heater
On/Off Circuit
Breakdown of Temp
Control Circuit
Erase lamp defective
Engine controller board
defective
Power supply fan
defective
Engine controller board
defective
defective
Exit fan
Engine controller board
defective
Laser unit fan ASSY
defective
Engine controller board
defective
Solution
Replace the HV Power
Supply PCB
Replace the LV Power
Supply PCB
Replace the fuser unit
Replace the engine
controller board.
Replace the LV Power
Supply PCB
Replace the engine
controller board
Confirm the connection of
Harness Connector
Connect the printer with
the rated voltage
source.
Connect the printer with
the rated voltage
source.
Replace the LV Power
Supply PCB
Replace the engine
controller board
Replace the LV Power
Supply PCB
Replace the engine
controller board
Replace the erase lamp
Replace the engine
controller board.
Replace the power supply
fan
Replace the engine
controller board.
Replace the exit fan
Replace the engine
controller board.
Replace the Laser unit fan
ASSY
Replace the engine
controller board.
Confidential