The power connector (with red and black wires) is difficult to remove without damaging it, unless you take a moment and understand how it works. Look at all of the photos for this step before continuing.

The connector is two pieces -- a white "male" piece (connected to the wires), and a beige "female" part (soldered to the main board).

There is a small "notch" in the female part, to give you a place to insert a small flat-head screwdriver. Put the corner of your screwdriver in there, and twist it gently to push the white part up (away from the main board). Do not try to pull it to the right (towards the battery board).

If it does not lift easily, try again with a smaller screwdriver. You might be pulling the female connector off the board, which will be difficult to repair.