raise the upper transport unit fully, then lower the transport to engage lock before you put your hands inside of the scanner.
2. pull the adf release lever toward you and lift up the adf sheet guide.
3. slide the pick roller unit to the left to disengage the clutch ring from the shaft.
4. pressing down on the upper part of the guide plate with your fingers at the two positions shown and then rotate the plate toward you to remove it.
5. hold and rotate the bail of the pick roller unit upward to release the lock.
6.pull the brake roller unit toward you to remove it.
7. wipe off the dust from the two discharge brushes: one at the pick roller side, the other at the brake roller side.
8. re-install the brake roller unit in the reverse order of its removal. by holding the bail toward you, put the brake roller unit into bracket and rotate down until it locks in.
9. install the guide plate in the reverse order of the removal. you should push it down and rotate back then the installation can be done smoothly.
10. lower the adf upper sheet guide slowly.
11. lift the upper transport unit fully to release the safety lock and then lower the transport unit carefully.