when injecting voltage to find shorts, as improper probing can permanently bridge high-voltage lines to low-voltage CPU data lines. power rail on this board?
: Offers a high-level overview of how the CPU, PCH (Platform Controller Hub), and peripherals like the display and storage interact. la-d402p schematic
: The ENE KB9022 chip (or similar) is the "brain" that manages the power button, keyboard, and battery charging. Finding the RSMRST# and PWROK signals on this chip's schematic page is the fastest way to diagnose a "no power" issue. Where to Find It: when injecting voltage to find shorts, as improper
If the laptop has no power but the 19V rail is present, the SIO or the BIOS chip itself may be faulty. : The ENE KB9022 chip (or similar) is
: Checking the LVDS/EDP connector pinout to verify if the backlight enable signal or LCD power is present. Bios/EC Issues