Works perfectly all through practice and then, next practice, it won't power up at all. I've gone through all sorts of cables, power cables, different outlets, and changing out the fuse and nothing works. When the switch is flipped, absolutely nothing happens. I popped it open to see if there were any outward signs of damage but I couldn't see any fried parts or anything like that. It was working perfectly for as long as I can remember until this - any ideas? could this be a costly one?