44015503TH  Rev. 1 
200 /
Oki  Data  CONFIDENTIAL
7.  TROUBLESHOOTING PROCEDURE
7.5.2.(8)  Two-sided printing jam (error code: 370, 371, 372, 373, 383)
(8-1)  Two-sided printing jam occurs immediately after the power is turned on.
Check item Check work
Action to be taken 
at NG
(8-1-1) Check condition of the paper running path
 Paper running path 
of the Duplex unit
 Chec
k if paper is jammed or not in the paper 
running path. 
Open the front cover and check if any paper 
remains in the Duplex feeder or not. 
Open the rear cover and check if any paper 
remains in the paper reversing path or not. 
Remove the Duplex unit. Check if any paper 
exists in the Duplex insertion slot or not. Open 
the cover of the Duplex paper running path and 
check if any paper remains inside of the Duplex 
unit.
 Remove the 
jammed paper.
(8-1-2) Check condition of the mechanical parts
Check the sensor 
levers of the 
respective sensors 
of the Duple
x unit.
Check if shape and movement of the sensor 
levers have any abnormality or not.
Replace the 
sensor lever 
with the good 
sensor lever.
(8-1-3) Check condition of electrical parts
Check the detection 
condition of the 
sensor signal. 
 Confir
m that the sensor signals are normally 
detected by using the SWITCH SCAN function 
of the self-diagnostic mode. 
For all sensors except the Dup-IN sensor, check 
the detection condition of the respective sensor 
in the two status: One is the status in which 
paper remains inside the Duplex unit. The other 
is the status in which paper is removed from the 
Duplex unit.
 Replace the 
Duplex board 
(V7Y PCB), 
or replace the 
defective sensor 
or connection 
cable.
(8-2)  Two-sided printing jam occurs during taking in the paper into Duplex unit.
Check item Check work
Action to be taken 
at NG
(8-2-1) Solenoid operation check
Duplex solenoid  Confirm that the Duplex solenoid works normally 
by using the Motor & Clutch Test of the self-
diagnostic mode.
 Replace the 
V
7Y board or 
solenoid.
Separator DUP 
(Paper unloading/
DUP paper taking-
in switching gate 
located immediately 
after the fuser unit)
Check visually movement of the gate by using 
the Motor & Clutch Test of the self-diagnostic 
mode. (EXIT SOLENOID) 
Check if movement is unsmooth or not, if 
amount of open/close is abnormal or not.
Replace the 
separator DUP.
ON/OFF timing of 
the Duplex solenoid
While the cover is in the opened state, perform 
the test print and confirm if the timing to open 
the separator DUP is correct or not.
Replace the WR 
sensor lever or 
solenoid.
(8-2-2) Sensor lever operation check
 Dup-IN sensor le
ver Open the rear cover. Touch the Dup-IN sensor 
lever to check if its movement is unsmooth or 
not.
 Replace the 
Dup-IN sensor 
lever
DUP-IN sensor Confirm that the sensor signals are normally 
detected by using the SWITCH SCAN function 
of the self-diagnostic mode.
Replace the 
Duplex board 
(
V7Y PCB), 
or replace the 
defective sensor 
or connection 
cable.
(8-2-3) Check condition of the paper running path
Paper inverting 
tr
ansport path 
Check that any foreign materials such as 
paper chip or blue do not exist that hampers 
the smooth movement of paper in the paper 
inverting transport path.
 Remove the 
foreign material.
(8-2-4) Motor operation check
 Duple
x motor Confirm that the Duplex solenoid works normally 
by using the Motor & Clutch Test of the self-
diagnostic mode. 
Open the rear cover and check rotation of the 
roller.
Replace the 
V
7Y board or 
motor.
Duplex pull-in/
reversing roller and 
its pinch roller
Check if the pull-in/reversing roller of the Duplex 
unit contacts or not with the pinch roller of the 
cover side when the Duplex rear cover is closed. 
(Does the pinch roller rotate when the roller is 
rotating?)
Replace the 
rear cover.