The heatsink crossbar comes right off, which gives us access to the motherboard shield.

The 5 screws on the two sides of the shield are swiftly removed with a Philips #2

The 2 screws on each side of the Game Pak slot are quite long, and are removed with a Philips #2.

With that, the shield slips right off, letting us gaze at the Nintendo 64's source of power.