I'm not sure I understand the description of the problem, but one thing I would recommend is keeping the computer open, i.e. just let the topcase/rest on top the board while it is plugged in. That way, you can verify your connections, try powering it on, unplug/plug in another connection, try powering it on, etc. Nothing is more frustrating that putting an iBook all the way back together only to realize something else is wrong and you have to go back in again.