today at rehesal i started playing and noticed 1 of the channels on my yamaha P322 power amp was not working, like it worked when it wanted to, but the led was on like the signal was going though and the clip led lighted when a big signal was there. anyone know what the problem can be? maybe i blown it? i brought it 2nd hand abut 4 month ago and never gave me problems, should i take it back were i brought it? or do you recomend me something to do 1st?