What is the most likely cause of a blown fuse? Long story that I won't get into, but it blows instantly when the amp is switched on. I dread bringing it to a tech and spending $$, since I was leaning toward selling this amp anyway. But if there is a chance it might be something simple, I am willing to take a crack at it. I know very little about amp electronics, but I can follow instructions, and I can solder.