Searchable engineering blueprints and power-on sequence timing charts can often be acquired from specialized databases such as Laptop-Schematics.com or peer-to-peer diagnostic boards.
If a specific USB port is dead, the schematic shows which controller manages that port, allowing for targeted troubleshooting. lad402p schematic top
The Input Current Sensing circuit and the primary 3.3V and 5V Always-On (ALW) standby power ICs. lad402p schematic top
Treat the schematic like a book—inputs on the left, outputs on the right—to reduce the "overwhelming" nature of a 10-channel design. Protection: lad402p schematic top