Things You'll Need
Instructions
Lay the controller face-down on a flat surface so the buttons are facing away from you.
Locate the screws in the back of the controller and remove each of them with a Phillips screwdriver. (The size of the screwdriver needed varies with the brand of controller).
Pull the back casing of the controller apart from the front to expose the buttons.
Squeeze the white clips on the sides of the controller motherboard and remove it from the case.
Examine the button locations and find the rubber flap that has come off of its button mold and realign it back on the button.
Insert the motherboard back into place and lock the clips back in by pressing down.
Reattach the back casing to the front and then reinstall the screws.