5018 Style - Fault Code: U7-1
|Technical Specifications||This fault code means the machine did not see the timing hole in the Photoreceptor Belt (PR Belt) come around at the right timing. The service manual calls this a �photoreceptor belt drive problem� but usually the problem is a sensing problem.
The light from the Precharge Erase Lamp needs to shine down through a small square hole in the edge of the PR Belt each time it comes around� The light then makes a 90 degree turn in a clear plastic light-pipe built into the front end of the copy cartridge, so that it shines on the Belt Hole Sensor (see Photo #3) on the front wall of the inside of the machine.
The most common cause by far is this: There�s a black mylar baffle which hangs down along the length of the Precharge Erase Lamp� it gets old and starts to hang down lower than it should, and it will start to curl around the lamp, blocking the light from shining down through the hole in the PR Belt. The machine then calls the fault �E2� and if you open the clamshell and close it again, you�ll see the U7 code. Usually it starts out intermittent, and later becomes a more constant problem.
The solution is to remove the Developer Unit and the Copy Cartridge (they both pull out of the right side door) and find the black mylar baffle. If it�s hanging down low or curling around the lamp, slice off the front 1-2 inches of the baffle using a razor, so that the light can get to the sensor. Also, clean the light pipe on the front end of the cartridge and the Belt Hole Sensor.