I own a fender frontman 15G amp. Its input power is 110V but my friend accidentally plugged it directly in a 220V outlet. It turned on for 10-15 seconds with a popping/cracking sound. i instantly plugged it out from the outlet and then tried to turn it on with my transformer (that converts 220V to 110V) but no lights, no power. By the way there was no burning smell or anything. i opens its back and checked the fuse, but its looks like its not blown. what could be the possible problem with it. plz help