DC power connector has slight damage

It's easy to remove the logic board of the A1278 13" model. Just be very careful when snapping out the little black connectors from their sockets (easy to damage). I don't use a spudger to remove them but a small needle that I insert in the front side of the connector and twist it a little on each side until the connector snap off. I never separated a socket from the board using that method. Use a spudger to remove all the other big "snap-on" connectors as indicated in the ifixit guide.

To remove the top case ribbon cable from its socket I use a scotch tape attached to the ribbon cable and pull on it to remove the cable once the socket retainer arm is up. I use the same scotch tape method to reinsert the cable in the socket.

The LVDS connector and socket are pretty fragiles so make sure to lift up the metallic retainer arm before trying to separate the connector from the socket. Just have to pull out the connector straight from the socket. When reinserting the connector to the socket, give just a little down angle to the connector before inserting it in the socket. DON'T force the connector in the socket...it should enter smoothly, if not try again, align, give a little down angle and insert. A good lightning helps...I use a small flashlight when connecting this cable.

Good luck !!