Subject: ASUS ROG G14 GA401 - hard short on +5VSUS

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.