Desolder the through hole-components in power plugs on both sides of the device where the batteries were once connected.

Do not refer to the pictures in this step for correct soldering and de-soldering techniques. They are solely for illustration purposes.

For proper soldering and desoldering techniques reference How To Solder and Desolder Connections.

Soldering requires the iron to be at hot temperatures and can cause burns. Wear safety glasses as needed.

Be extremely careful with the cables in this step as they could melt, burn, or break.