Apple LaserWriter 12/640 PS - Manual (Page 177)

IMPORTANT Other possible configurations may produce diagnostic errors
when the printer starts up or may produce unexpected results.
If you want to You need this much printer memory
Turn on PhotoGrade or use the 12 MB
duplex printing option
Turn on PhotoGrade and duplex 20 MB
print on all size paper (except legal)
Turn on PhotoGrade and duplex 24 MB
print on all size paper (including legal)
Removing the printer’s side cover
1 If necessary, turn the printer so that the left side is accessible.
2 Locate the two Phillips screws on the back of the printer.
3 Unscrew and remove the screws. Put them in a safe place.
4 Open the top cover of the printer.
Remove both
of the Phillips screws.
WARNING Make sure the printer is turned off.
152 Chapter 5