HP CLJ9500 exits paper to wrong finisher tray

[Deer John]

Bizarre....This networked MFP randomly delivers jobs, (sometime in the middle of one) to the top tray in reverse order. As if an invertor solenoid or gate was sticking open. Began when another company replaced the finisher exit roller assy. Other company then suggested firmware update...customer updated firmware.Problem disappeared for a week or so...came back...they call us.. So... I replaced the whole 3000 sheet staple stacker (#c8085a) Problem disappeared for 2 weeks and has returned. Considering an exorcism but would entertain better ideas.

[Wild Bill]

Just a thought; Lets say it is not the stacker causing the problem. What would cause this on the machine side?
Possible DC Controller? What controls the signal to switch those gates? Just throwing that out there.

[Iowatech]

You might check the rubber pads for the solenoids and their linkages in that area. If the rubber pads are sticky enough, they can prevent the solenoid from releasing in time to let the paper exit into the proper tray.