You need to match the board to the diagrams. We don't know what version your PS2 is.

Only 1 wire of the 8 wire mod is likely to be common so don't get too excited there!.

because you need to solder onto the main CPU chip, remember you need a .1 or .12mm tip on a 15w iron with 33 or 35 swg wire (enamelled copper is easiest to work with). And a pair of razor blades to isolate each CPU leg as you work.