Dead MacBook Air, ideas on what else I can do?

Apple MacBook Air "Core 2 Duo" 1.86 13" (Late '10)

As the subject says, dead.

- Doesn't power on (no sound, screen, caps lock, nothing)

- Magsafe LED is on when plugged in, green

- Opened, nothing immediately obvious

I'm thinking either the logic board, or the IO board. More likely to be the logic board as it just died from one minute to the next.

So, suggestions welcome on anything else to try, best places to source replacement parts.

Cheers!