Intermittent "Laser Failure"error displayed on LCD. Requires cycling power to clear error. Grinding or ratcheting noises that may occur with or without a "Laser Failure".

CAUSE:

Anything that affects movement of the main drive assembly may cause a "Laser Failure". This failure will occur if the printers' paper drive path becomes loaded down due to any one of the following;

a. A high torque developer unit or OPC Drum.

b. A defective or "toner covered"tractor sensor.

c. The main drive motor is weak or defective.

d. The low voltage power supply or something which is loading down the 24 volt power supply line.

e. Laser Scan Unit (LSU) interface cable broken at the hinge.

SOLUTION/PROCEDURE:

a. Developer Unit - OPC Drum:

A high torque developer may also cause a loud grinding or ratcheting noise. This condition can be caused by toner that has settled or packed in the developer mixing area. This may occur after installing new toner.

The short term fix may be to remove the developer. Hold it over a trash can at an angle that makes the toner compartment lower than the magnetic roller (the exposed roller with toner on it), the roller should be horizontal as well. Alternately shake th e unit, tap the side of the unit, and push the top of the white gear on the right side away from you. It is sometimes helpful to "rock"the gear back and forth a bit and then forward many turns. The unit should actuate more freely after this procedure. Reinstall the unit and clear the "Laser Failure"message by cycling the power. This may correct the problem temporarily or permanently, if not replace the developer unit.

The doctor blade gap may not be set correctly. If you feel the doctor blade is not adjusted correctly, an adjustment procedure is available.

The OPC Drum could cause a high torque condition. Inspect the OPC Drum, this should also turn freely by hand.

b. Tractor Sensor.

This condition is usually characterized by the form advancing only .5"(at start up) then stopping with the error displayed. The compartment where the tractor sensor is located is next to the waste toner bottle compartment. Therefore, the sensor compart ment can become full of toner making the sensor intermittent or completely inoperative.

c. Main Drive Motor Assembly.

Replace the main drive motor assembly.

d. Low Voltage Supply.

The 24 volt line could be bad or loaded down. Items that may load down the supply could be a bad cooling fan, Laser Scan Unit (LSU) and High voltage (HV) power supply. In the case of a bad HV power supply, the frequency of laser failures may change with increase or decrease of the intensity control set ting (green knob).

e. LSU cable.

Opening and closing the door may affect how often the error occurs. Check and/or replace the LSU cable. The open cable may cause the error when the power is on. And it may also cause the display to block out completely.