Oki B721 Maintenance Manual

Oki Data CONFIDENTIAL
45487001TH Rev.1
6-25 /
6. Troubleshooting procedure
Panel display Cause Check details
Result
Solution
Service Call
121: Error
High-voltage power
supply I/F error.
Is cable between PU
board and high-voltage
power unit connected
properly?
Is there no improperly
connections?
No
Ye s
No
Connect properly.
Check improper
connections for
high-voltage.
Replace the hige-
voltage power
supply.
Service Call
122: Error
Low-voltage power
supply FAN error.
Low-voltage power
supply temperature
error.
Is the FAN (bottom
right of the front) of
the low voltage power
supply block working?
Is the FAN connector
connected correctly?
No
Ye s
No
Ye s
Check connections
for connector of
the FAN.
Replace the low-
voltage power
supply.
Replace the FAN.
Replace the low-
voltage power
supply.
Service Call
123: Error
Abnormal
environment humidty
/Not connected
humidity sensor.
Does error reoccur? Ye s
Power Off/On.
Replace the control
panel board (PCQ
board).
Service Call
124: Error
Abnormal
environment
temperature.
Does error reoccur? Ye s
Power Off/On.
Replace the control
panel board (PCQ
board).
Power Off/On
126: Error
Condensation in
the printer was
detected.
Condensation iss likely
to occur in printers
carried from the outside.
Turn on the printer
again after it is exposed
to room temperature for
two hours to half a day.
Does the error reoccur? Ye s
After leaving the
printer at room
temperature, turn
on the power
again.
Replace the control
panel board (PCQ
board).
Service Call
127: Error
Error detected at the
fuser unit cooling
FAN.
Is the FAN connector
connected properly?
Does error reoccur?
No
Ye s
Ye s
Connect properly
again.
Replace the FAN
motor.
Replace the PU/
CU board.
Panel display Cause Check details
Result
Solution
Service Call
128: Error
Error detected at the
engine FAN motors.
05: Fuser side FAN
08: REAR FAN
0B: ID FAN 2
Is the FAN connector
connected properly?
Does error reoccur?
No
Ye s
Ye s
Connect properly
again.
Replace the FAN
motor.
Replace the PU/
CU board.
Service Call
134: Error
LED head fault
detected.
(134=K)
Is LED head properly
set?
Does error reoccur?
No
Ye s
Ye s
Set properly for
LED head unit.
Turn power ON
agein.
Replace LED head
unit
Service Call
155: Error
Fuser unit
fuse cannot be
disconnected.
Is fuser unit set
properly?
Does error reoccur?
No
Ye s
Ye s
After cleaning for
fuser connector,
reset.
Turn power ON
again.
Replace the PU/
CU board.
Service call
163: Error
Error detected
by toner sensor.
(163=K)
This error does
not occur with the
factory default
settings.
Is toner cartridge
setting?
Is toner lock lever
setting?
Does error reoccur?
No
No
Ye s
Set toner cartridge.
Turn a lock lever
of toner to a fixed
position.
Replace toner
sensor or
assembly.

Oki B721 Specifications

General

Print Technology	LED
Resolution	1200 x 1200 dpi
Processor	533 MHz
Memory	256 MB
Connectivity	USB, Ethernet
Duplex Printing	Standard