The guitar that came in our Rock Band bundle suffered from the downward strum issue that many people have reported online. Either the strum bar on the guitar doesn't recognize a downward strum at all or it will recognize each downward strum twice. Not the best situation to be in when playing a rhythm-based game.
EA is offering free replacements for anyone who got a bad guitar; however, that would mean shipping it back and waiting for a new one to arrive. I figured it would be easier to fix it myself.
The whole process took about five minutes, and the only tools needed were a regular-size Phillips screwdriver and a small Phillips jeweler's screwdriver.Step 1: Remove the 16 screws on the back of the guitar
There are 16 screws that line the edge of the guitar's plastic case. You'll need to remove each of these to get inside.
Step 2: Remove the back of the guitar
With all of the screws removed, the back of the guitar easily lifts off.
Step 3: Tighten the screw holding the microswitch in place
The downward strum problem occurs when the microswitch that registers each strum gets loose and fails to make contact with the strum bar. If your microswitch isn't making contact, simply loosen the screw slightly, rotate the microswitch counterclockwise, and then tighten the screw back down.
You will need the small Phillips head jeweler's screwdriver for this step.
NOTE: There is a microswitch on each side of the strum bar. To fix the downward strum problem, you want to tighten the one ABOVE the strum bar.Step 4: Reattach the back of the case
Replace the back of the case and tighten the 16 screws you removed in Step 1.Step 5: ROCK!!!
That's it! Your Rock Band guitar should now strum properly in both directions.