OKI C831n

Jam occurs immediately after the paper feed is started. (1st tray)

Check condition of the paper running path

Check item	Check work	Actions to be taken at NG
Paper running path of the front unit	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 levers of the paper entrance sensor 1 and the paper entrance sensor 2.	Check if shape and movement of the sensor levers have any abnormality or not.	Replace the sensor with the good sensor lever.
Check the feed roller, pickup roller and the retard roller assembly of the tray.	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 or the pickup roller has worn out or not.	Replace the feed roller, the pickup roller and the retard roller assembly of the tray.

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 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.

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 halfway 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.

Clutch operation check

Check item	Check work	Actions to be taken at NG
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 CU/PU board, or replace the paper feed solenoid.

Check the system connection

Check item	Check work	Actions to be taken at NG
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 HOPLC connector (2) of the CU/PU board and check the following at the cable side. Short circuit between pin-1 – FG Remove the HOPCL connector (2) of the CU/ PU board and check that approx. 240Ω can be measured between pin-1 and pin-2.	Replace the clutch and assembly it again correctly.