OKI C831n

Jam occurs immediately after paper feed is started. (Multipurpose tray)

Check condition of the paper running path

Check item	Check work	Actions to be taken at NG
Paper running path of the multipurpose tray	Check if paper is jammed or not in the paper running path.	Remove the jammed paper.
Sheet Receive of the multipurpose tray	Confirm that the Sheet Receive has moved up normally. Confirm that the support spindle and spring of the Sheet Receive have been installed in the specified positions normally.	Correct installation of the above parts so that the Sheet Receive moves up to the specified position normally.

Check condition of the mechanical parts

Check item	Check work	Actions to be taken at NG
Check the sensor levers of the paper entrance sensor 2 and the WR sensor.	Check if shape and movement of the sensor levers have any abnormality or not.	Replace the sensor with the good sensor lever.
Front cover	Confirm that the locks in the right and left of the front cover are locked normally.	Replace the font cover assembly
Check the feed roller, the pickup roller, and the retard roller	Check if any foreign materials such as paper dust on the surface of the feed roller or of the pickup roller or not.	Remove the foreign material.
	Check if the feed roller has worn out or not.	Replace the feed roller.

Motor operation check

Check item	Check work	Actions to be taken at NG
Paper feed motor	Confirm that the paper feed motor works normally by using the Motor & Clutch Test of the self-diagnostic mode.	Replace the CU/PU board, or replace the paper feed motor.
Paper feed motor driver	Remove the MOTERCL connector (1) of the CU/PU board and check the following at the connector side. Several MΩ between pin-5 – FG. Several MΩ between pin-6 – FG. Several MΩ between pin-7 – FG. Several MΩ between pin-8 – FG.	Replace the CU/PU board.
MPT clutch	Carry out Motor & Clutch Test to check if the MPT clutch works normally.

Check the system connection

Check item	Check work	Actions to be taken at NG
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.
Paper feed motor drive cable	Check that any cable is not pinched during assembling of the printer. Remove the MOTERCL connector (1) of the CU/PU board and check the following at the cable side. Short circuit between pin-5 – FG Short circuit between pin-6 – FG Short circuit between pin-7 – FG Short circuit between pin-8 – FG	Replace the cable with the good cable that normalizes the connection condition.
Paper feed motor	Remove the MOTERCL connector (1) of the CU/PU board and check that approx. 3.4Ω can be measured between pin-5 -pin-6 and pin-7 -pin-8 respectively at the cable end.	Replace the paper feed motor.