Apple ColorLaserWriter 12/600PS - Manual (Page 255)

If you still can’t find the problem in any of the places identified on the status
panel, the paper jam may be inside the paper cassette. (Sometimes a sheet of
paper gets tangled while still in the cassette.) Slide the paper cassette out of
the printer. Inspect the stack of paper, and remove any paper that is
misaligned.
If you have installed an optional 250-sheet feeder, see “Clearing Paper from
the Optional Feeder,” later in this chapter.
Check both paper
cassettes and remove
any paper that is misaligned.
Standard paper
cassette
Universal paper
cassette
232 Chapter 11