This circuit operates even when the computer is off. It provides the "wake-up" signal power.
For specific disassembly layouts, refer to HP's Maintenance and Service Guides . ps42419ha schematic work
Because this PSU contains high-voltage capacitors that can hold a charge after being unplugged, follow these safety steps: This circuit operates even when the computer is off
This integrated circuit (IC) manages the standby voltage. If the PSU provides no standby voltage (0V on the green/purple wires), this IC is often blown. Replacing it with a slightly more robust 20W version is a common fix. Because this PSU contains high-voltage capacitors that can
Always use a discharge tool (like a high-wattage resistor) on the primary capacitor before touching the board.
Incoming AC passes through a fuse and an EMI filter to remove noise. A bridge rectifier then converts it to high-voltage DC (around 145V–160V depending on load and region).