HP QMS 1660E - Manual (Page 144)

Media Input
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QMS 1660E Print System Reference 6-10
4 Pull out the lock buttons on the cassette supporter until you
hear them click.
The lock buttons are located on the bottom-left and bottom-right
of the cassette supporter.
5 Place the cassette supporter on a flat, stable surface with the
cassette installation slot toward you.
6 Fit the holes on the bottom of the paper feeder onto the
extrusions on the cassette supporter.
Lock
Extrusions