Epson Progression U12 - Manual (Page 97)

3. Position the coprocessor over the socket as shown below.
Align the notched corner of the coprocessor-marked with
the orientation (index) dot-over the corresponding comer
in the socket.
Index dot
Caution
Be sure to align the pins in the coprocessor directly over
the holes in the socket. If you insert the math coprocessor
in the wrong position, you could permanently damage it.
4. Make sure the pins in the coprocessor are directly over the
holes in the socket. Then gently push the coprocessor
straight into the socket, pressing evenly on all sides.
5. Reinstall the CPU card as described on page 3-19.
3-28 Installing and Removing Options