PunchOut!!! The Real Installation...

Step 8 Post-controller destruction

Go out, buy new controllers, bring them back and rip them apart to see if they're going to work or not... It's really important how the connection pads are designed on the inside of the controller. Unfortunately, you can only check once you unscrew and take the controller apart. You need to make sure that there's "lots" of space to solder wires that will not touch the opposite pads.