Asus X407UBR No Power

[abuhamza]

I have a ASUS X407UBR will not power up.

I have measured:

+3VA = 3.3 V
+3VA_EC = 0,8V

Need guidance where to start troubleshooting next. thanks

LINK to schematic/boardview https://www.badcaps.net/forum/troubl...-0#post1751795

[mon2]

Remove all power. Meter in resistance mode.

Measure the resistance to ground of +3VA_EC.

[abuhamza]

Remove all power. Meter in resistance mode.

Measure the resistance to ground of +3VA_EC.

It's 1.3 KOhm

I measured :

+3VAO = 3.3 Volt
+5VAO = 2,8 Volt

The weird thing is that, after plugging and then removing the charger, resistance of +5VAO went very low to 11 ohm, but gradually get higher after some time back to 1800 ohm

[mon2]

Review if this +5VAO rail is linked to the usb ports and usb vbus load switches. Inspect for damage in this region. Often, by spec, there will be a bulk cap on each usb vbus rail (usb type A connector). Maybe a partially shorted cap on one of these usb ports.