Hey everyone, I've been playing Guitar Hero since the first one came out, and have an Xbox 360 that is kept alive so I can continue doing so. The guitar controller I have that's in best condition has had issues with the green fret button for years now. When I went to play just now, it took several attempts just to launch the game from the Xbox home screen, so I finally decided to take things apart and look at it, however I think the fix I found can be accomplished without disassembling anything (though it requires basic soldering knowledge, and taking apart the neck of the guitar is very easy and will give you more room).
On the left is what the little contactor board originally looked like; note the divots in the center of each pad where the spring-loaded pins on the body of the guitar press against. The right one is the one that I experimented on, you can just barely make out the divots left in the bead of solder I put on each contactor. The contact pads seem to be too thin for how strong the springs for the pins are; a little solder gives the pins a fresh surface to make a good connection, and much more material to push through (even if the pin does wear all the way through, there will be enough solder surrounding it to make a good connection).
After ~2 hours of playing just now, no issues on any of the fret buttons!
Hope this helps someone! Rock on! 🤘🏾