No boot following logic board replacement

I have a friend's 2006 macbook that died after a bad device was plugged in to the USB port (an external DVD running on an external power adapter using the wrong voltage). The macbook went dark instantly, followed by a distinct aroma of electric death from the vicinity of the USB ports. The macbook could not be roused after that, so I gambled that the logic board was fried and purchased a used replacement from a "reputable" eBay vendor.

Long story short.. the new-to-me logic board is installed, but the macbook still doesn't do anything. What might I be missing (besides two hours from my life and $115)?

The magsafe light goes green when it's connected. It doesn't boot either with the battery only, magsafe only, or both connected. No lights, no sounds, etc.. just nothing.

I should add that I have also followed the SMC reset procedures that are listed on Apple's site.

I have lots of experience tearing apart PC hardware, but this is my first rebuild of a Macbook (which, I must say, is really well designed). Any ideas??

 

Thanks for that tip.. I tried to short the power pads on the board, without success.

Thinking along the same lines, on a PC I would disconnect almost everything from the MLB, including RAM, to see if I could elicit any life from the board (expecting a diagnostic beep code, at minimum). Does this work on one of these boards? If I disconnected Wifi, drives, display data, inverter, RAM and even the magsafe board, should I expect to get some kind of noise, or even spinning CPU fan, by powering the MLB from the battery only?