Oki MC770 series Maintenance Manual - page 181

45376001TH  Rev.1 

180 /

Oki  Data  CONFIDENTIAL

7. Troubleshooting and repair procedure

Check item

Check work

Action to be taken 

at NG

(7-1-4) Check the system connection

 Signal cable for relay 

board, EXIT sensor 

cable

Check that FFC is normally inserted at the 

RELAY connector 

 of the PU board and at the 

PU/CU IF connector 

. 

Check that the relay board and the EXIT sensor 

are normally connected.

Normalize the 

connection 

condition.

Signal cable for relay 

board, EXIT sensor 

cable

Confirm that the cables are not pinched, sheathes 

are not peeled off, and they are assembled 

normally.

Replace the 

connecting cable 

and normalize 

the assembled 

condition.

(7-2) Paper unloading jam occurs after a paper is taken into printer.

Check item

Check work

Action to be taken 

at NG

(7-2-1) Check condition of the paper running path

Face Up Stacker 

Cover

  Confirm that it is either fully opened or fully 

closed  

Eliminate any 

in-between 

condition of the 

cover between 

the fully open 

position and fully 

closed position.

Duplex pull-in gate

Confirm that the Duplex pull-in gate works 

normally by using the Motor & Clutch Test of the 

self-diagnostic mode. 

Is it set to the paper unloading side normally?

Replace the 

Duplex pull-

in gate or the 

Duplex solenoid

Rear panel

  Check that the installation condition of the rear 

panel hampers smooth movement of a paper in 

the paper running path, or not.

 Remove the rear 

panel and re-

install it.

Paper running path 

of unloading unit

Check that any mechanical load does not exist 

that hampers the smooth movement of paper in 

the paper running path of the paper unloading 

unit, by the visual inspection. 

Check if the paper unloading motor becomes 

difficult to rotate or not.

Correct the 

portion that 

becomes 

mechanical load.

Check item

Check work

Action to be taken 

at NG

(7-2-2) Check condition of the mechanical parts

 Sensor lever of the 

paper exit sensor

  Check if shape and movement of the sensor 

levers have any abnormality or not.

  Replace  the 

sensor lever with 

the good sensor 

lever.

(7-2-3) Motor operation check

 Fuser  motor 

  Confirm that the fuser motor works normally 

by using the Motor & Clutch Test of the self-

diagnostic mode. 

Check if any load exists or not.

Replace the PU 

board or fuser 

motor or 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.

(7-2-4) Check the system connection

Fuser motor drive 

cable

Check the connection condition of the cables. 

PU board DCHEAT connector  , 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.

  Fuser  motor 

  Replace  the 

fuser motor.