Asustek X540UP notebook is not turned on for repair

Machine model: ASUS x540up

Fault phenomenon: notebook no booting

Maintenance process: ASUS x540up

notebook no booting.Power on detection standby 3V 5V, click Switch no power on, found 3vsus_Pwrgd was lowered to 0.4V or so.

Asustek X540UP notebook is not turned on for repair Figure 1.

Check Boardview, connect to these places.When removed to d5804, 3vsus_Pwrgd recovered to 3.3V.

Asustek X540UP notebook is not turned on for repair Figure2.

It is known that 1.0 vsus is needed first_Vs3us high level, pwrgd_Pwrgd doesn’t pull down.It’s from pu8302. 12 pin 5V is normal, 8 pin en3.3v is normal, 9 pin top 0V is abnormal. Replace 620k resistor as 0V, and trace up 19v without voltage.

Asustek X540UP notebook is not turned on for repair Figure3.

After running the line, you can see that there is a broken line, but you need to remove the auto power off capacity to make up, directly Jump wire, power on test,Normally booting up.