Epson 500 Series - Manual (Page 61)

2. Place the coprocessor over the socket so that the round
indentation indicating pin 1 is in lower right corner. Then
push it down into the socket.
3. Replace the keyboard as described in the next section.
The computer automatically detects when a coprocessor is
installed. When you turn on the computer, the system
configuration screen shows that a numeric coprocessor is present
Caution
If you need to remove the math coprocessor,
yourself. This procedure requires a special extraction tool.
Contact your Authorized EPSON Servicer.
4-16 Connecting Optional Devices