ASUS x455lj notebook triggered power down repair

Machine model: ASUS x455lj

Fault phenomenon: notebook switch auto power off

Maintenance process:
ASUS x455lj notebook switch auto power off, power on switch, the current up to 50mA auto power off.

ASUS x455lj notebook triggered power down repair Figure 1.

After testing each VCC, it is found that the VCC is only 0.75V, and the Boardview is displayed as 1.5V VCC.Looking forward,VCC is not correct,VCC is from 3vs, measuring 3vs is also wrong.

ASUS x455lj notebook triggered power down repair Figure2.

3vs is converted from pq9116. 2 pin should have 10V more than VCC for opening. The opening is connected by pr9102 below.

ASUS x455lj notebook triggered power down repair Figure3.

There is more than 10V on one end of pr9102, but not on the other side. When measuring pr9102, it turns to 490m. If you change a resistor, it still doesn’t work. It seems that pq9116 is broken.This MOSFET is not easy to find,Parts motherboard did not find the direct Jump wire, so the standby current will be more points.

ASUS x455lj notebook triggered power down repair Figure4.
Power on, the current is more than 700mA, the external connection is normal, ASUS x455lj switch,auto power off,VCC,convert transistor are damaged.The repair was successful.