La-c781p Schematic ((link)) Here

These can short to ground, preventing the 19.5V from reaching the rest of the board.

Use the search function (Ctrl+F) to follow signals like PM_PWRBTN# or ALL_SYS_PWRGD . La-c781p Schematic

"Always-on" rails required for the Super I/O and BIOS. +1.35V: Dedicated power for the DDR3L memory modules. +1.05V_VCCST: Sustained voltage for the CPU. +VCC_CORE: The main power supply for the processor. These can short to ground, preventing the 19