Lanier 6725

If you open the duplexer cover, you will see a photo interupt sensor on the right. Stick a piece of paper in it. Take the waste bottle out, so you can see the inside of the duplexer. Turn the machine on. A minimal amount of waste toner will fall, and can be easily cleaned up. There are two stacker guides in the duplexer. One stacks lengthwise, the other widthwise. If memory serves me correctly, the horizontal guide not moving, or the sensor not sensing movement causes that error. If the guide moves, the sensor is probably dirty or bad.