Oki B721 Maintenance Manual

Oki Data CONFIDENTIAL
45487001TH Rev.1
6-49 /
6. Troubleshooting procedure
Check item Check work
Actions to be taken
at NG
(3-2-4) Check the system connection
Paper feed motor
drive cable
Check the connection condition of the cable.
Check if the connector is connected in the half-
way only or not, and check if the connector
is inserted in a slanted angle or not. Check
also that cables are assembled without any
abnormality.
Replace the
cable with the
good cable
that normalizes
the connection
condition.
(3-2-5) Clutch operation check
Paper feed clutch,
registration clutch
Check to make sure that the paper feed clutch
or registration clutch works normally by using
the Motor & Clutch Test of the self-diagnostic
mode.
Open the front cover so that the rollers can be
seen to check.
Replace the
PU/CU board,
or replace the
paper feed
solenoid.
(3-2-6) Check the system connection
Clutch cable for
paper feed
Check the connection condition of the cable.
Check if the connector is connected in
the half-way only or not, and check if the
connector is inserted in a slanted angle or not.
Check also that cables are assembled without
any abnormality.
Replace the
cable with the
good cable
that normalizes
the connection
condition.
Cable for paper
feed clutch
Check that any cable is not pinched during
assembling of the printer.
Remove the HOPCLT connector
of the PU/CU
board and check the following at the cable side.
Short circuit between pin-1 – FG
Remove the HOPCLT connector
of the PU/
CU board and check that approx. 240
Ω
can be
measured between pin-1 and pin-2.
Replace the
clutch and
assembly it
again correctly.
6.5.2.(4) Feed jam (Error 380)
(4-1) Jamoccursimmediatelyafterthepoweristurnedon.
Check item Check work
Actions to be taken
at NG
(4-1-1) Check condition of the paper running path
Paper running path
of the front unit
Open the front cover check if paper is not
jammed in the paper running path.
Remove the
jammed paper.
(4-1-2) Check condition of the mechanical parts
Check the sensor
levers of the paper
entrance sensor 1,
that of the paper
entrance sensor
2 and that of the
WR2 sensor.
Check if shape and movement of the sensor
levers have any abnormality or not.
Replace the
sensor with the
good sensor
lever.
(4-1-3) Check condition of electrical parts
Check the detection
condition of the
sensor signal.
Confirm that the sensor signals are normally
detected by using the Maintenance Menu
SWITCH SCAN function.
Replace either
the PU/CU
board or the
front sensor
board (HSC-
2 PCB) or
connection
cable.
Check the output
signal levels of the
paper entrance
sensor 1, that of
the paper entrance
sensor 2 and that
of the WR2 sensor.
Check for the following signals at the FSNS
connector
of the PU/CU board.
Pin-4: Paper entrance sensor 1
Pin-3: Paper entrance sensor 2
WR2SNS connector
Pin-2:WR2 sensor
Confirm that the above signal levels change
when the sensor lever is operated.
Replace the
front sensor
board (HSC-2
PCB)
Check the power
voltages supplied
to the front sensor
board (HSC-2
PCB)
Check the 5V power at the FSNS connector
of the front sensor board (HSC-2 PCB).
Pin-1: 5V power supply
Pin-5: 0VL
Replace the
connection
cable.

Oki B721 Specifications

General

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