Yeah, that's the same pic of the amp I found Googleing, it's absolutley no help, lol. I want to see the sides of the amp where the buttons, swithes and knobs are to see if you have something set wrong.
Does the amp smell burnt? The smell of smoked electronics is a pretty unique smell, one that's hard to describe in words, but you know it when you smell it if you know the smell, if that makes sense.
Are you sure the wires haven't come off the sub or the box terminal inside the box? Try popping the sub with a battery, use a 9volt if you have one.