Epson 3865X Plus - Manual (Page 138)

Align the notched comer of the coprocessor with the
notched comer of the coprocessor socket. The notched
corners must be aligned for the coprocessor to fit into the
socket, so be sure the alignment is correct before you
proceed to the next step.
Caution
If the math coprocessor is inserted in the wrong position,
it could be permanently damaged.
5. Gently push the coprocessor into the socket, pressing
evenly on all sides of the coprocessor, as shown below.
If the coprocessor does not go in smoothly, do not force it-
pull it all the way out and try again, keeping it straight as
you insert it.
It is completely inserted when the surface of the coprocessor
is flush (even) with the surface of the socket. Examine the
coprocessor to be sure it is inserted all the way into the
socket.
5-32
Installing and Removing Options