1. Observation method: there is no burning, burning, foaming, plate surface broken line, socket rust.
2. Meter test method: Is the 5V and GND resistance too small (below 50 ohms)?
3. Power inspection: For the clear broken board, the voltage can be slightly increased by 0.5-1V, and the IC on the board can be rubbed by hand after startup to make the chip in question heat up, so as to perceive it.