Often an ISL88739. If the laptop runs on battery but won't charge, or vice versa, this is the primary component to inspect.
If a short is found on DCBATOUT, use a DC power supply to inject 1V and use thermal imaging or isopropyl alcohol to find the heating component. Schematic Symbols and Layout Navigation lad711p rev 10 schematic top
Revision 1.0 boards sometimes suffer from corrupted ME (Management Engine) regions, leading to 30-second delay boots or fan-spin-but-no-display issues. Diagnostic Steps Using the Schematic Often an ISL88739
Diodes (Check for shorts in the protection circuits). R/C Series: Resistors and Capacitors. Safety and Precision Schematic Symbols and Layout Navigation Revision 1
Generated by the TPS51225R (or similar) controller. These must be present before the laptop can trigger the power-on sequence.
The Embedded Controller manages the power button signal and keyboard. If the board is unresponsive, check the VCC and RST signals on this chip.
The main system rail (19V or battery voltage) that feeds all other regulators.