My MacBook Pro 15" Unibody Mid 2009 died, so I followed the suggestions I've seen on the internet: replace I/O board,...

Did replacing the logic board do it? I've replaced the i/o board as you did; the logic board; and even the keyboard, thinking maybe there was some kind of short in the on/off button. Still dead. Symptom is bright green magsafe turns to very dim green after a couple minutes. Machine does nothing.