Hi,

I'm troubleshooting an ASUS ROG G14 GA401 motherboard and I'm looking for advice from someone who has seen many of these boards.

Current situation

The board is completely dead.

I traced the problem to the +5VSUS / standby power area.

Measurements performed

PU8701 (SN51285ARUKR)

I originally suspected PU8701.

I removed PU8701 completely from the board.

After removal:

The short is still present.

VO1 / +5VSUS side still measures almost shorted to ground.

Pin 14 (VO1 / +5VSUS) reads approximately 005-006 in diode mode to GND.

Pin 8 (SW2 / +3VA_DSW section) does not show the same low reading.

Because the short remained after removing PU8701, I assume PU8701 itself is probably not the root cause.

PL8701 isolation

I removed PL8701 to separate the regulator output from the rest of the rail.

Results:

One side of the coil measures around 006 to GND.

The other side measures around 001 to GND.

This seems to indicate the heavy load/short is located on the +5VSUS rail side.

MOSFET checks

I checked:

PQH8701

PQL8701

Both appear normal and do not seem shorted.

TPS22968 load switch (PU8801)

I also investigated the 3VA_DSW load switch:

PU8801 = TPS22968

Measured all pins in diode mode against GND

Results:

Pin 1,2 = 002

Pin 3 = 714

Pin 4 = 002

Pin 5 = 714

Pin 6,7 = 002

Pin 8,9 = 859

Pin 10 = 1203

Pin 11 = 002

Pin 12 = 1203

Pin 13,14 = 819

I also injected voltage into VIN pins:

Pins 1/2 = only about 0.039 mA

Pin 4 = about 0.039 mA

Pins 6/7 = about 0.132 mA

Nothing became warm.

Because of that, I am currently not convinced PU8801 is the source of the fault.

Voltage injection

I injected voltage directly into the shorted +5VSUS rail.

Tests:

0.3 V → current draw present

0.5 V → about 300 mA

0.8 V → current immediately rises to current limit (~500 mA)

The rail behaves almost like a direct short.

I used cooling spray / propane-butane method to look for a hotspot.

Result:

No obvious component heats up.

EC does not get warm.

No visible hotspot anywhere.

Question

Since PU8701 is removed and the short remains on +5VSUS:

What are the most common failures you have seen on GA401 boards causing a hard short on +5VSUS?

Is there a known IC on this rail that commonly fails?

Would you continue isolating +5VSUS loads one by one, or increase injection voltage/current further?

Have you ever seen the EC or PCH create this type of symptom on this platform?

Any advice would be greatly appreciated.

Thanks 

Posted picture Is mosfet , And drain / source Is shorted ,(mosfet removed , checked outside thé board And Its ok , short on the board on the other hand Is still present.