OKI C531

Jam occurs immediately after the paper feed is started.

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
Hopping sensor, IN sensor and WR sensor lever check	Check the sensor lever shapes and operations for any problem	Replace the sensor lever(s) with proper one(s).

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 selfdiagnostic mode.	Replace the CU/ PU board or the feed motor.
Paper feed motor driver	Pull out the CU/PU board HOP connector 1, and check the following at the side of the connector: 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 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. Pull out the CU/PU board HOP connector 1, and check the following at side of the cord: Short circuit between pin-1 – FG Short circuit between pin-2 – FG Short circuit between pin-3 – FG Short circuit between pin-4 – FG	Replace the cable with the good cable that normalizes the connection condition.
Paper feed motor	Pull out the CU/PU board HOP connector 1, and check whether there is a resistance of approximately 3.4Ω or 5Ω between the pins 1 and 2, and between the pins 3 and 4, at the cord side.	Replace the paper feed motor.