You have six pins on the motherboard where there is usually the power connector, connect the pack to the line written 12v, connect the output from the regulator to the 3.3v line and the ground to any ground point on the board. The real problem is that if the led works doesn't mean the console works, the led is on 3.3v but what if the 12v doesn't works? You will not know, like I said you have to put a game on a screen to be sure!