HP Deskjet 9800 Printer series - Manual (Page 118)

3 Remove the rear cover from the duplex unit (if installed), remove any paper, and replace the rear
cover. If the paper jam is not visible by removing the rear cover, remove the duplex unit to locate
the jam.
4 Lift up the output tray and remove any jammed paper from the input tray.
108 6 Troubleshooting