Once the cover is removed, locate the motherboard on the back shell (the left component in the third image). The motherboard will be the middle component as shown in the third image.

To extract the motherboard, remove the seven Phillips head screws used to fasten the motherboard to the unit.

The battery is located on the motherboard. Two wires, red and black, are soldered onto a small PCB (printed circuit board) connecting the battery to the motherboard.

Be aware of the power button that is located between the back shell and the motherboard on the lower right corner.