Someone answered saying:
Most likely one or more of the output transistors failed, that's been my experience with two AB amps I've repaired that were blowing fuses on power up. If you can determine which transistor failed a replacement may only be a few bucks. If you don't feel up to troubleshooting the individual components like that a replacement plate amp from parts express is probably your best bet.
Anyone know a cheap way to check a transistor? and which one they are in the pics?