So far i had success swapping with a NES control pad PCB as suggested here (http://www.famicomworld.com/forum/index.php?topic=6399.0).
Now i'm considering swapping with the board inside one of these cheap USB clones (http://www.ebay.com/itm/Classic-Gaming-Controller-Joypad-Gamepad-For-Nintendo-NES-Windows-PC-MAC-SW/142182654668), since i use the gamepad with PCs only.
Do you know if the screw holes on these 3rd party PCBs match the original case?
(or maybe other 3rd party gamepads that are compatible?)