Xbox Series S Getting to Idle Boot
If you do not get the normal boot up sequence (drawing about 2.5A then settling to 10mA once initial 12V is applied) then you need to check all power regulators in the Initial Power Up guide.
A common issue is if you have a dead-short on a rail such as the 12V, 5V, 3.3V, 2.5V or 1.8V rails you will not see the power regulators relying on them come up to voltage.
If you do not get 12V check for shorts on your 12V rail.
If you only get 12V rail but no 5/3.3/2.5 or 1.8V rails, it is usually a short on the 5V rail.
If you get the 12V and 5V rail but some of the other rails, check for shorts on the outputs of each of the 3.3/2.5 and 1.8V rails.