I recently got a Yorkville Bassmaster 200 combo from ebay, when I first got the amp I plugged in and everything was fine, the problem now is that sometimes when I turn it on nothing happens, other times it will sound fine and then all of a sudden start crackling and breaking up and then I lose the sound. Also when I unscrew the head part of the amp and wiggle it around the sound will sometimes come back which leads me to belive that it is probably something really simple which drives me crazy. Has anyone had similar problems or maybe knows what the problem is? I would hate to have to trash this amp that I just got. Oh, and also I do not have a warranty on this amp as I bought it from ebay used.