I didn't find your model#, but found the 2000, 4000, 6000, 8000 SuperCubes.
Have you tried all inputs (LFE, line-level, high-level)? Have you considered the possibility of a lightning strike? Most likely, it was a voltage spike as the result of the power flicker, causing inrush current spikes. Those spikes are damaging. Power line filters absorb most of these types of spikes before they can do damage, but they may not stop lightning. If your equipment is connected to one that includes a warranty for equipment damage, you may be covered. You may also want to gain access to the amp's internals to see if there's a blown fuse, even though the light is on.