If it blew the fuse while not even turned on, that means the power supplies were still charged up from the last time, and that was enough to pop the new fuse.
Resistors never burn up on their own, something always causes it. Most likely shorted transistors in the circuit. Am I right, this power amp is the board with the square holes in the center, and transistors all around the holes bolted to the heat sink? I generally just go around the whole collection testing each part for shorts. But quite often small transistors near the edge burn up too. There are small resistors that burn up.. seem to recall some small vvalue resistors there. Little zeners blow.
Sounds like the voice coil on your speaker has melted.