ASUS B85M-F fan is running normally, and it does not light up for maintenance

ASUS B85M-F fan is often turning, the point is not lit, brushing the BIOS, replacing the PQ804 fault still exists, so replace a new PQ800 everything back to normal.

Machine model: ASUS B85M-F

Symptom: After triggering, the fan has been spinning and does not light up

Maintenance process: the measurement of the major voltages is normal, the CPU power supply is also out, the first brush BIOS, the fault is still the same. Next check the power management chip, the chip is ASP1252, 10 feet for the PG signal, along the 10 feet to find the PQ804, remove and find that it is broken, replace it with a new, boot, find that the fault has changed, become a fan to turn for a few seconds after stopping, can be triggered again.

Remove the PQ801, the tube controls the EN voltage, and successfully lights it up after triggering, which shows that a new fault point should occur after heating, because the previous EN is normal. PQ801 is connected to PQ800 through a 10K resistor, PQ800 is removed, it is found that it is also damaged, and after replacement, everything is normal.