Laserjet 8000/8100 & feeder unit removal

Hi

Is there some simple procedure to remove whole paper feeder unit from HP LJ
8000/8100 ?
I´d like to refurbish or change rollers between pickups and registration.
They are impossible to access without deassembly.

Are errors 13.5 and 13.9 caused by feed problems before registration (Check
right door message) or are they caused by delays on post-fusing rollers ?

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Janne
j j j @ i k i . f i