Brother MFC-9420CN Service Manual page 237

Error Code
(Hex)
Waste toner box full or
73
un-device
OPC belt exchange
74
Fuser unit exchange
75
Transfer roller
76
120K Kit exchange
77
PF Kit2 exchange
78
Wasted toner box near-full
79
(exchange)
Top cover open error
7A
Rear cover open error
7B
Not used
7C-7F
AT the start of FAX message
80
printing, the controller detects
that paper is smaller than A4
size in length.
Recording paper jam. (The
81
paper width sensor stays ON
even after completion of paper
ejection operation.)
(Not used.)
Recording paper jam in paper
82
pull-in operation
(The paper width sensor fails
to detect the leading edge of
paper.) (Not used.)
83 Recording paper jam.
(The registration sensor comes
ON too early in the paper
feeding operation.)
Symptom
9 - 1 0
Probable Cause
The waste toner box is
not assembled.
The waste toner box is
full.
Replacement timing of
the OPC belt.
Replacement timing of
the fuser unit.
Replacement timing of
the transfer roller.
Replacement timing of
the 120K kit.
Replacement timing of
the PF Kit2.
The waste toner box is
nearly full.
The top cover is
opened.
The rear cover is
opened.
Paper smaller than the
specified size loaded in
the paper tray
Main PCB defective
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---
Paper is not correctly
set in the paper tray
Separation pad
damaged
Registration sensor
actuator unhooked
Main PCB defective
Solution
Assemble the waste toner
box.
Replace the waste toner
box with a new one.
Replace the OPC belt with
a new one.
Replace the fuser unit
with a new one.
Replace the transfer roller
with a new one.
Replace the 120K kit with
a new one.
Replace the PF Kit2 with
a new one.
Replace the waste toner
box with a new one.
Close the top cover.
Close the rear cover.
Load the correct size of
paper.
Replace the main PCB.
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---
Reload paper.
Replace the paper tray.
Set the registration sensor
actuator into place.
Replace the main PCB.
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