@fuchsiii @faizalr I suspect the power managment system to have issues.

Basically what goes between the external 20VDC-in, VBAT and VDCpower internal (I assume 12V/5V/3,3V rails)...

Pretty shure there's something like a #ISL9239 / #ISL9240 or TI-made PMUX that goes from those two power rails - or at worst there's just one and the VBAT & Power Rail gets spliced out of one voltage downconverter...

At this point I'd consider looking up https://laptopblue.vn or other sites for #schematics and #BoardViews like #LouisRossmann does...