My buddy was too lazy to look online for solutions, and actually fix his rock band guitar - so I stole it, the game, his other guitar, and his mic. It wouldn't register down strums, and as you know, up strumming an entire song is just no fun.
I have to give credit to Ben Sones from Quarter To Three. His fix was the inspiration to mine. Plus his seems more reliable.
Step 1: Open it up!
Step 2: Finding the contact!
The strummer works by leveraging the other side to push contacts together, which then allow signal to be sent to the XBOX. The problem was that my contacts weren't contacting eachother.
Now remember, the contacts for the down strum are up, and vice versa.