Ursprünglicher Beitrag von: rdklinc ,
Are you getting a light on the AC adapter? I'd disconnect the power button from its corner and press it, just to make sure the problem isn't that it's not seated correctly. If that doesn't work, I'd re-seat the keyboard cable, which is what connects the keyboard and power button to the logic board. It has to go pretty far into the socket, so perhaps it's not all the way in. If that doesn't work, you can always trigger the power-on pads with a metal object while the keyboard connector is disconnected. This tests whether or not the board is working by itself, separate from the topcase hardware. You can find a link to a picture of the power-on pad location at the bottom of this page: http://rdklinc.com/answers/discussion/19/re-your-macbook-keyboard-replacement-tutorial If it powers on, you know the board is good, and the problem is with your topcase or related hardware. Also, if you have a second topcase from the other machine, you might want to try swapping that, but I'd only do it if the board powers up successfully via the power-on pads.