Apple LaserWriter 12/640 PS - Manual (Page 161)

3 Lift up the back end of the duplex printing unit and slide the metal brace onto the post.
The brace is located on the left side of the duplex printing unit near the back.
4 Unpack the duplex printing unit key.
5 Remove the three covers located in the back of the printer. Remove the two top covers
by inserting the key into the side of the covers and pushing gently on the key (the covers
will snap off). Remove the bottom cover by inserting the key into the bottom side of the
cover and pushing downward (you may need to use some force to remove this cover.)
IMPORTANT Be careful when removing the covers so that they do not fall
inside the LaserWriter 12/640 PS.
Insert the key
into these slots.
2 Attach this brace
1 Raise the door.
to the post.
136 Chapter 5