Thanks for the info. I believe that the power supply is good but I can test for sure by swapping into the good IIci. The motherboard is cosmetically in very good condition, but in all likelihood it's damaged to such an extent that it won't be worth even trying. I imagine that such cracks as you have mentioned could be so small that they would be invisible to the naked eye.

I don't have that particular machine with me at the moment, but I'll try replacing caps and see what difference that makes. If that doesn't work, I may need to consider finding a new logic board, or just leave it because it's an attractive machine even when not running.