Oki B721

Oki Data CONFIDENTIAL
45487001TH Rev.1
6-28 /
6. Troubleshooting procedure
Panel display Cause Check details
Result
Solution
Service Call
254: Error
An unexcepted error
occurred during
initializing the
security mode. Error
cause information
was displayed after
an error number.
Does error reoccur? Ye s
Power Off/On.
Regenerate an
encryption key. If it
doesn’t solve the
problem, replace
the PU/CU board
or encrypted HDD.
Service Call
257: Error
An unexcepted error
occurred during
initializing HDD.
HDD Error cause
information was
displayed after an
error number.
Does error reoccur? Ye s
Power Off/On.
Format the HDD
again. If it does not
solve the problem,
replace the HDD.
Power Off/On
901: Error, 902:
Error
Short or open in
Internal thermistor
detected.
Is internal thermistor
cable setting proper?
Does error reoccur?
No
Ye s
Ye s
Connect cable set
properly again.
Turn power ON
again.
Replace the
internal thermistor.
Power Off/On
903: Error, 904:
Error
Abnormal
temperature
detected by Internal
thermistor
(high-temp or low
temp.)
Is internal thermistor
cable setting proper?
Does error reoccur?
No
Ye s
Ye s
Connect cable set
properly again.
Turn power ON
again.
Replace the
internal thermistor
and leave aside for
30 minutes.
Then turn power
ON again.
Power Off/On
911: Error, 912:
Error
The Geared Motor
Error at the Optional
Tray.
911:Tray2
912 Tray3
Is the indicated tray
installed properly?
Does error reoccur?
No
Ye s
Ye s
Install the optional
tray properly.
Turn power ON
again.
Replace the
Geared Motor of
indicated tray.
Panel display Cause Check details
Result
Solution
Power Off/On
918: Error
An error was
detected with the
Duplex Fan Motor.
Does error reoccur?
Does error reoccur
after power restoration?
Ye s
Ye s
Power Off/On.
Check if the FAN
is connected
properly.
Replace the FAN.
Power Off/On
923: Error
An error was
detected with the
image drum motor
by overload. Does error reoccur
after power restoration?
Does error reoccur
after power restoration?
Ye s
Ye s
Check if the image
drum is installed
properly.
Replace the image
drum unit.
Replace the ID
motor.
Power Off/On
928: Error
An error was
detected the Fuser
Motor rotation by
overload. Does error reoccur
after power restoration?
Does error reoccur
after power restoration?
Ye s
Ye s
Check if the
fuser is installed
properly.
Replace the fuser.
Replace the fuser
motor.
Power Off/On
933: Error
Tray2 CPU Clock
Frequency Error
Does error reoccur
after power restoration?
Does error reoccur
after power restoration?
Ye s
Ye s
Replace the unit.
Replace the PU/
CU board.
Power Off/On
934: Error
Tray3 CPU Clock
Frequency Error
Does error reoccur
after power restoration?
Does error reoccur
after power restoration?
Ye s
Ye s
Replace the unit.
Replace the PU/
CU board.
Power Off/On
935: Error
Tray4 CPU Clock
Frequency Error
Does error reoccur
after power restoration?
Does error reoccur
after power restoration?
Ye s
Ye s
Replace the unit.
Replace the PU/
CU board.
Power Off/On
941: Error
A watch dog timer
error was detected. Does error reoccur? Ye s
Power Off/On.
Replace the PU/
CU board.
Power Off/On
942: Error
An undefined
interruption was
detected.
Does error reoccur? Ye s
Power Off/On.
Replace the PU/
CU board.