Often an ISL88739. If the laptop runs on battery but won't charge, or vice versa, this is the primary component to inspect.
Located near the DC-in jack on the top side. If these short, the laptop will not draw any current from the adapter. lad711p rev 10 schematic top
The Embedded Controller manages the power button signal and keyboard. If the board is unresponsive, check the VCC and RST signals on this chip. Often an ISL88739
When working on a LAD711P Rev 1.0 board, focusing on the top-side schematic and layout is critical because it houses the primary power rails and the CPU/PCH complex. Understanding the LAD711P Power Rail Hierarchy or vice versa