OKI C931

Jam occurs immediately after a paper is taken into printer.

Check condition of the paper running path

Check item	Check work	Actions to be taken at NG
Paper running path between the registration roller 2 and the fuser	Check if paper is jammed or not in the paper running path.	Remove the jammed paper.

Check condition of the mechanical parts

Check item	Check work	Actions to be taken at NG
Check the sensor lever of the paper entrance sensor 3 and EXIT1/EXIT2/ EXIT3 sensors.	Check if shape and movement of the sensor levers have any abnormality or not.	Replace with a normal sensor lever.

Motor operation check

Check item	Check work	Actions to be taken at NG
Feed motor driver and belt motor driver	Confirm that the hopping motor, belt motor and fuser motor work normally by using the Motor & Clutch Test of the self-diagnostic mode. Check if any load exists or not.	Replace the PU/ CU PCB, the faulty motor of either feed motor or belt motor, or the belt unit.
Feed motor, REG2 Clutch	Remove the FDMRG2CL connector of the PU/CU PCB and check the following at the connector side. Several MΩ between pin-1 – FG Several MΩ between pin-2 – FG Several MΩ between pin-3 – FG Several MΩ between pin-4 – FG	Replace the PU/ CU PCB.

Check the system connection

Check item	Check work	Actions to be taken at NG
Feed motor drive cable, belt motor drive cable, fuser motor drive cable	Check the connection condition of the cables. PU/CU PCB FDMRG2CL connector, DCBELT connector, DCHEAT connector Visually check if each connector is connected in the halfway only or not, is inserted in a slanted angle or not. Also check that cables are assembled without any abnormality.	Normalize the connection condition. Replace with a normal cable.
Feed motor drive cable, belt motor drive cable, registration clutch 2 driver cable	Check that any cable is not pinched during assembling of the printer. Remove the FDMRG2CL connector of the PU/CU PCB and check the following at the cable side. Short circuit between pin-1 – FG Short circuit between pin-2 – FG Short circuit between pin-3 – FG Short circuit between pin-4 – FG Short circuit between pin-5 – FG Remove the DCBELT connector and check the following at the cable side. Short circuit between pin-1/-2/-3/-4/-5/-6/ and FG Short circuit between pin-2 – FG	Replace with a normal cable and normalizes the assembled condition.
Feed motor, registration2 clutch	Remove the respective connectors from the PCB, and confirm that the following resistance exists between the corresponding pins, at the cable side. PU/CU PCB FDMRG2CL connector Between pin-1 and pin-2: Approx. 3.4Ω Between pin-3 and pin-4: Approx. 3.4Ω PU/CU PCB Between pin-5 and pin-6: Approx. 240Ω	Replace the feed motor or belt motor.