HP M551 duplex jam

[dpackman]

This machine properly feeds and prints a single duplex sheet and will also print multiple sheets if they are complex enough to go through slowly. At speed, however, the sheets seem to interfere with each other and jam.

I have tested all the detector switches and they all work. Suggestions for more diagnostics would be appreciated.

[dpackman]

There is a solenoid that works in concert with a spring to move a dual plastic set of page diverters. It seems that a combination of a slightly sticky solenoid and a somewhat old and tired spring made this movement a bit too sluggish for reliable page redirection at speed. Some quick jiggling of the solenoid decreased its stickiness and it seems to be back to working order now. Perhaps a new spring would be helpful in the longer term.