Gently pull the motherboard away from the lens.

Flip the camera over.

Connecting the motherboard to the front case are seven wires.

Desolder the seven wires.

If you are only removing the motherboard as an intermediate step to get to other components, do not desolder yet, as not all wires need to be removed.

Be careful when desoldering the wires. If you do not know how to properly desolder a wire, seek help to prevent damage to the motherboard. Also, make sure the soldering crunches don't fall into the lens case.