Is there any one single part inside of an amplifier that is the usual suspect when the fuses blow? This happens when the speakers are not hooked up. They also blow when sitting on a test bench, so I know there is nothing wrong with the connections.
Usually a dead short somewhere, possibly due to a broken solder point and some of the wires are touching. Look at the power supply for starters, and work your way down. Or just send the amp in for repair.
I've looked over the whole board, and everything looks fine. I don't see any burned or shorted parts. I thought it might be inside of a coil or something to that effect.