Amp quit working, any electronics gurus?

[doubt at inwave.com (Nate Mellom)]

I have a Alpine 3520 mono amp I've had for years (bought used, never 
hooked it up).  In my pre-Cincy rush, I installed my Pioneer DEH-P6000 
in-dash head unit, and ran wires to run the amp, to power a Pioneer 
spare-tire sub.  Last Saturday, I hooked everything up, the amp powered 
up, and the sub worked (only the head unit was permanently installed, I 
was testing the amp and sub before installation).  Sunday morning, the 
amp won't power on.  I have:

12v hot running directly from the battery for power (fused, fuse is fine)
12v remote trigger from the head unit
Single pair of RCA cables to supply signal to the sub
Good ground (ground to a taillight mounting bolt)

Voltage tests and continuity tests all agree, I'm getting battery 
voltage (power and trigger), and my ground is sound, so I'm assuming for 
some reason my amp took a crap.  I pulled off the cover, nothing looks 
or smells burnt, and the on-board 30 amp fuse is fine.

Any ideas what I should check on the amp?  Could it be fixed?  I'm 
shopping for other cheap mono amps, but I'd like to get the Alpine 
working, it fits PERFECTLY in the first aid kit hole in my Mk2.

Nate