Simply remove 6 screws on the the bottom of the unit. (They are under the rubber feet / covers.) This is for Version 1 2 3 only.

(If your machine does not have 10 screw covers located at the bottom and only 8 screw covers then its version 4 5 or 6. Click here for more info.)

Now lift the bottom of the ps2 off (you may need to remove a sticker), then remove the one screw below so you can remove metal shield to expose the board.

Match your board with one of the versions of the boards below.
After soldering the wire to each of the matching spots, close the unit up and your done!