A friend of mine got Rock Band, and the yellow drum stopped working after about an hour of play. We have no idea how to fix it. We pulled off the cover (it easily detaches and reattaches) but there doesn't seem to be a clear reason for the malfunction. We pulled open a working drum (red) and there is no obvious difference between the two (ie damage or a cause for the problem). We put the red drum back on and it works still. Anyone have this problem?