Oki B721 Maintenance Manual

Oki Data CONFIDENTIAL
45487001TH Rev.1
6-58 /
6. Troubleshooting procedure
6.5.2.(10) Fuser unit error (Errors 167 to 177)
(10-1) Error occurs immediately after the power is turned on.
Check item Check work
Actions to be taken
at NG
(10-1-1) Thermistor is defective Note)
Upper thermistor,
lower thermistor,
side thermistor,
heater thermistor
Check the respective thermistors if they are
shorted or opened internally.
Check the resistance value at the connector
pins in the bottom of the fuser unit.
(Refer to section 9.1 Resistance value (fuser
unit).)
Replace the
fuser unit.
If any attempt of
using new fuser
unit as a trial
is going to be
made, be sure to
use the System
Maintenance
Menu FUSE
KEEP MODE.
Installed condition
of fuser unit.
Check if the fuser nit is pressed in until the
connector in the bottom of the fuser unit is
surely connected.
Re-set the fuser
unit.
Note! Service calls 171: Error and 175: Error can occur when the printer temperature
is below 0˚C. Turn on the power again after the printer temperature has
increased.
(10-2) Error occurs approx. 1 minute after the power is turned on.
Check item Check work
Actions to be taken
at NG
(10-2-1) Temperature increase of fuser unit
Thermostat, heater Heater of the fuser unit is controlled of its
temperature. Check if the fuser unit gets hot
or not by touching it with hands.
If the fuser unit temperature does not increase
and remains cold, check that the resistance
between pin-1 and pin-4 and between pin-3
and pin-2 is about 1 to 3
Ω
, between pin-2 and
pin-4 is about 4 to 7
Ω
respectively. (Refer to
section 9.1 Resistance value (fuser unit).)
Replace the
fuser unit.
If any attempt of
using new fuser
unit as a trial
is going to be
made, be sure to
use the System
Maintenance
Menu FUSE
KEEP MODE.
(10-2-2) Temperature increase of fuser unit
Installation position
of the Lower
thermistor
The Lower thermister must be installed while
contacting with the fuser unit. Check if the
lower thermister is installed in the far position
from the specified position or not causing
detection of the lower temperature than the
actual temperature of fuser unit.
Replace the
fuser unit.
If any attempt of
using new fuser
unit as a trial
is going to be
made, be sure to
use the System
Maintenance
Menu FUSE
KEEP MODE.

Oki B721 Specifications

General

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