Motherboard self-protection caused failure

After the computer is turned on, the host's LED is not bright, the power supply fan does not turn, the hard drive also did not self-test sound. The reboot is attempted many times and the failure persists.

The first to check the external AC power, the voltage is too high or too low, may cause the power to protect themselves, with pencil and multimeter first detect power sockets, power line voltage, if all normal.

Then the case is opened, the power switch and the reset key inside the metal contact plate to check, contact and whether there is a power supply short circuit phenomenon. The motherboard, memory, CPU, and video card are then checked to see that the problem persists.

The power and CPU are detected on another computer and no fault is found. After the power is back, check the motherboard of each battery cable signal whether there is a loosening of the situation, boot or black screen. The CMOS battery line is discharged and the power is turned on again, and the fault is resolved.