I just bought a Mesa Boogie Dual Rectifier off of ebay a about a week ago. It worked great when it arrived. However, after the second day of playing it I had an abrupt loss of power in channels 2 and 3. Channel 1 works fine. There is some sounding coming out of 2 and 3 and they seem to be working but like I said the volume is minimal at best. Does anyone have an idea whats going on here??? Did some of the tubes go bad???