Ceramic filtering MLCC capacitors. On this board, look closely at the filtering capacitors near the CPU buck converter phases or the GPU power supply. PC40, PC42, or similar high-voltage ceramic capacitors frequently crack internally and short to ground.
You see the two differential pairs (USB_P and USB_N). You know Pin 3 on J_USB1 goes to Pin D15 on the PCH. But the trace passes through three hidden vias and two layers. You cannot find the break. la6582p boardview full
and schematic are indispensable tools to diagnose these issues, rather than just replacing the entire motherboard. What is LA-6582P Boardview? Ceramic filtering MLCC capacitors