Okay, have isolated the problem a bit. beachycove wins the guessing game. I pulled the Ethernet card before reinserting the logic board this time and it started right up. I was sure I had already tried that, but apparently in all the excitement I had only fired 5 times, not six The Ethernet card looks almost brand new, so I don't think it's the problem. However, those two caps that I didn't replace pn the logic board are located right at the end of the PDS slot. Seems a fair likelihood that they're on the same circuit as the PDS slot and may be the cuplrit. Anyone know what size they are? They're labeled 100 6V so I'm guessing they're 100 microfarad caps rated at 6 volts. I really don't have the right tool to test them even after I've pulled them so the plan is simply to replace them once I verify their capacitance.