NEO-POWER-0

Photo stolen from Photobucket user kyo_244.

NEO-POWER-0 is an add-on board found in some late first generation home consoles (NEO-AES board).

It was probably added to prevent users from frying their system by using 9V power supplies.

The board itself is a simple step-down converter, allowing to safely use voltages up to 12V.

The circuit was then included as part of later revisions of the main board.

Pinout

Red: 5V out. Yellow: 7.5V to 12V. Black: ground.