Search U5D1 . The BoardView shows pin 2 is P_12V . Pin 9 is EN (Enable). Pin 13 is +5V_Standby .
Search for VIN (Main 12V input). Find C3C1 (a large capacitor near the power connector). boardview xbox one s
Plug in power supply (120W internal PSU). No amber light on the console. Search U5D1