Good point there is that the voltages could be out of whack. I haven't adjusted them for optimal, as a matter of fact I reset them to what they were when I received the system, but only visually... i'm still not sure what "optimal" is. If I can get some documents describing the optimal settings for these, i'll be sure to give them a shot. Apple's service source documents show how to perform the adjustments, and the figures they should read at, but unfortunately they require one of Apple's internal test tools.
I wouldn't be surprised if the board was dead however... the ports on the back look pretty shabby.
I may be able to secure another logic board anyway, should I need it.