Epson EQUITY 386/33 PLUS - Manual (Page 54)

3. Position power supply connector P4 so the large tab on the
connector faces the right side of the computer. Beginning
with the six pins toward the back of the computer, carefully
line up the holes in the connector with the pins in the socket
and then push in the connector.
If you do not correctly align the holes with the pins in
the socket, you could severely damage your computer
4. Connect power supply connector P5 to the remaining six pins
in the socket using the same procedure.
3-12 Accessing Internal Components