Then we check if the boot current of the motherboard is normal. Power up the motherboard with a Direct Current Supply. When the probes touch the main power supply circuit of the motherboard and the boot-up hasn't been triggered, the current directly jumps to 2.7 A.

We can confirm that the main power supply circuit of the motherboard is short-circuited, leading to the not turning on issue. Then we measure the diode values of the main power supply circuit with diode mode of the multimeter. The diode value is 534, which is normal.

When measuring a nearby capacitor, the diode value is 0. It indicates that the circuit is shorted.