I have a Hp 15 laptop day11a motherboard that is dead. I have 19.5v vin and +3VPCU. I am not getting S5 to switch 3.3v/5v on. I have NBSWON1# which drop to 0v when powerbutton pressed. Rsmrst 0v. I have tried to flash kbc but programmer cannot see it.
What other signals need to be present?. When I inject 3.3v into S5_on the both regulators output 3.3v/5v but unit still no leds or switch on.

Виновником оказалась u27. После замены все заработало.