NEO-POWER-0 is an add-on board found in some late first generation AES consoles.
It was probably added to prevent users from frying their consoles by using power supplies giving more than 5V.
The board itself is a simple step-down converter, allowing to safely use voltages up to 12V.
The circuit was then included in later revisions of the main board.
Red: 5V out. Yellow: 7.5V to 12V. Black: ground.