Xbox original power transistor, a very common component to fail causing no power - or if someone has swapped a v1.6 board into a v1.0 - v1.5 case causing a short, this will rectify the fault providing there is no damage on the underside of the board.
This product requires professional installation and should NOT be attempted by amateurs.
Due to the high possibility of user error. There are NO RETURNS ACCEPTED under ANY circumstances once the item has been removed from the packaging