If one capacitor had exploded and a second one was about to go, then it could be a sign of overvoltage. If so, then you have to worry about what else is connected to the same capacitors.
If it helps, here is the service manual:http://www.electronica-pt.com/images/fbfiles/files/MS_SC_AKX50LB_K_1_.pdf
A quick look and it looks like there are two switching supply circuits so I guess one is for standby power and the other is the main supply for the amplifier. If there is a fault, it could be in either supply, or something could be dragging down a supply forcing the micro to shut everything down.
Or some other random problem that again results in the micro deciding to shut down.
If you get stuck, nothing beats posting up a circuit with measured voltages on a whole lot of nodes, if that is possible. Definitely try and capture the voltage on all the major power rails before the system does shut down.