10) Fuser Unit Error (Errors 167 To 177); Fuser Unit Error (Errors 167 To 177); Error Occurs Immediately After The Power Is Turned On; Error Occurs Approx. 1 Minute After The Power Is Turned On - Oki B721 Maintenance Manual

Oki Data CONFIDENTIAL

6.5.2.(10) Fuser unit error (Errors 167 to 177)

(10-1)

Error occurs immediately after the power is turned on.

Check item
(10-1-1) Thermistor is defective Note)
Upper thermistor, Check the respective thermistors if they are
lower thermistor, shorted or opened internally.
side thermistor, Check the resistance value at the connector
heater thermistor pins in the bottom of the fuser unit.
(Refer to section 9.1 Resistance value (fuser
unit).)
Installed condition Check if the fuser nit is pressed in until the
of fuser unit. connector in the bottom of the fuser unit is
surely connected.
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.
45487001TH Rev.1
Actions to be taken
Check work
at NG
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.
Re-set the fuser
unit.
(10-2)

Error occurs approx. 1 minute after the power is turned on.

Check item
(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 3Ω, between pin-2 and
pin-4 is about 4 to 7Ω respectively. (Refer to
section 9.1 Resistance value (fuser unit).)
(10-2-2) Temperature increase of fuser unit
Installation position The Lower thermister must be installed while
of the Lower contacting with the fuser unit. Check if the
thermistor 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.
6. Troubleshooting procedure
Actions to be taken
Check work
at NG
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.
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.
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