HP Color LaserJet 8550DN input device failure,

This error message indicates a lifter malfunction has occurred. When the 2000-sheet input tray (Tray 4) is closed, the paper deck lifts the paper stack until it is just below the feed rollers. Photosensor flag PS34, the paper surface photosensor, determines when the paper stack is lifted into the feed position. When PS34 does not detect paper in the expected time, the printer reports a 66 error. SOLUTION: Follow the steps below to troubleshoot and resolve the issue.

1. Turn the printer off, open and close the tray, then turn the printer back on to see if the error clears.
2. Open the drawer and check for extra paper or items stored on the left side of the tray. This will prevent the tray from lifting due to excess weight or blocking the lift of the tray.
3. Remove all the paper from the tray. Remove the tray guides and reseat them. Verify the guides are not bent or broken.
4. Lift the paper deck manually to verify there are no obstructions in the path.
5. Pull the tray out as far as possible and observe the white bushing on the back right side of the tray. If the white bushing is broken, the tray will not lift properly.