Samsung CLX-8640 series Service Manual page 416

4. Troubleshooting
ii) Pull the lever and release the pick up Assy.
iii) Push and release the Stacker Assy.
iv) Remove the Guide Pick Up Upper after removing 4 screws.
v) Check if the sensor is assembled correctly. If the sensor is defective, replace it.
7) Check if the simplex scan sensor connector is connected correctly.
8) Close the DADF unit.
4-257 Copyright© 1995-2013 SAMSUNG. All rights reserved.