Most of the time issues such as this revolve around the common failure ICs (M92, BQ, P13)
I would be checking your soldering on all these ICs, as I often see boards where people have attempted replacements on these ICs and have inadvertantly bridged pads together or pads are open not connected to the board. If your not sure, you could remove the M92 IC as the console will oridinarily still boot without it, battery only.
I believe you can do the same thing with the P13 IC and the console will still boot without it.
Failing that, if you suspect the SoC then you can follow along with this thread here,
and let me know the resistance to ground on the main rails on the inductors surrounding the PMIC.