Originally, the battery needed replaced, then, after ruining the logic board by not seeing your instructions on the matter, I replaced the logic board.
With the help of your repair info, it went very well and my backup restored all my info to the new logic board. That was major!
My issues were with 1) Disconnecting the two flat ribbon connectors from the logic board. At that time, I did not understand that there was a "retaining flap" to flip up and I tried to pry the whole thing up like some of the other connections. OOPs. Here are your instructions. Had I read this, I may have gotten this right.
Use the edge of a plastic opening tool to flip up the retaining flaps holding the digitizer ribbon cables in their sockets on the logic board.
Be sure you are flipping up the retaining flap, not the socket itself.
Pull the digitizer ribbon cables straight out of their sockets. 2) I almost messed up the side ribbon connector also but your instructions saved that one. Have fun!