Asus , board 532lws R1..3 Power rail 5v , 3v dsw

[User 4574]

Hi everyone .
I have model g712l And In stuck.
Originally this laptop has a short on main Power rail . Thé main short is gone, i have found 2 pea16b mosfets Next to the SN51285ARUKR shorted , and the Chip Intself was Also shorted , i have removed them and main Power rail IS not shorted anymore , but right Now im still eating for this parts And in checking rest of the board . But pin 14 od the SN51285ARUKR when this chip od removed is shorted to ground Its +5VSUS has 6ohms , And that can not be , i have check mosfets All over the board And i have found ONLY one tahat ís shorted its pea16ba shorted source to drain . Its locsted next to the PCH , mosfet od removed measured And Its ok , short present .

Hi everyone,

I have an ASUS ROG G712L motherboard and I am stuck with a power rail issue.

Originally the laptop had a hard short on the main power rail (AC_BAT_SYS). After troubleshooting, I found two PEA16BA MOSFETs next to PU8701 (SN51285ARUKR) shorted source-to-drain. The PU8701 controller itself also appeared damaged.

I removed:

• PU8701 (SN51285ARUKR)
• both PEA16BA MOSFETs

After removing these components, the main AC_BAT_SYS short disappeared completely.

I am currently waiting for replacement parts, but while checking the rest of the board I found something strange.

With PU8701 completely removed from the board:

• Pin 14 (VO1 / +5VSUS sense) measures almost shorted to ground.
• The +5VSUS rail measures approximately 6 Ohms to ground.
• PL8701 was removed during troubleshooting.
• The MOSFET side (LX node) measures normal.
• The +5VSUS side still measures very low resistance.

I started isolating loads from the +5VSUS rail:

• PU8201 (NB692GD-Z) isolated -> no change
• PU8601 (DDR regulator) isolated -> no change
• PU8302 (+1.05VSUS regulator) isolated -> no change
• PCE8701 removed -> no change

The +5VSUS rail still measures around 5.8-6 Ohms.

I also injected voltage into +5VSUS:

• 1.0V -> ~0.175A
• 1.5V -> ~0.255A

The current increases linearly and nothing gets noticeably hot.

Another thing I found:

There is one more PEA16BA MOSFET located near the PCH area which measures shorted on the board. After removing it and testing it out of circuit, the MOSFET itself is good, but the short remains on the motherboard side.

At this point I am unsure whether:

1. 5.8-6 Ohms on +5VSUS is actually abnormal for this platform.
2. There is still another load connected to +5VSUS that I have not isolated.
3. The fault is somewhere in the +3VA_DSW / +5VSUS generation area.
4. I may have damaged an internal PCB layer when the original PU8701/MOSFET failure occurred.

Has anyone worked on this platform and knows what resistance is normally expected on +5VSUS with PU8701 removed?

Any advice would be greatly appreciated.

Thank you.Hi everyone,

I have an ASUS ROG G712L motherboard and I am stuck with a power rail issue.

Originally the laptop had a hard short on the main power rail (AC_BAT_SYS). After troubleshooting, I found two PEA16BA MOSFETs next to PU8701 (SN51285ARUKR) shorted source-to-drain. The PU8701 controller itself also appeared damaged.

I removed:

• PU8701 (SN51285ARUKR)
• both PEA16BA MOSFETs

After removing these components, the main AC_BAT_SYS short disappeared completely.

I am currently waiting for replacement parts, but while checking the rest of the board I found something strange.

With PU8701 completely removed from the board:

• Pin 14 (VO1 / +5VSUS sense) measures almost shorted to ground.
• The +5VSUS rail measures approximately 5.8-6 Ohms to ground.
• PL8701 was removed during troubleshooting.
• The MOSFET/LX side of PL8701 measures normal.
• The +5VSUS side still measures very low resistance.

I personally believe the remaining fault is somewhere on the main +5VSUS power rail.

I started isolating loads from the +5VSUS rail:

• PU8201 (NB692GD-Z) isolated -> no change
• PU8601 (DDR regulator) isolated -> no change
• PU8302 (+1.05VSUS regulator) isolated -> no change
• PCE8701 removed -> no change

The +5VSUS rail still measures around 5.8-6 Ohms.

I also injected voltage into +5VSUS:

• 1.0V -> ~0.175A
• 1.5V -> ~0.255A

Current increases linearly and behaves as expected for roughly 5.8 Ohms.

Unfortunately I do not own a thermal camera, so I cannot easily identify a hotspot. I tried voltage injection and cooling spray, but nothing becomes noticeably warm.

Another thing I found:

There is one more PEA16BA MOSFET located near the PCH area which measures shorted while installed on the board. After removing it and testing it out of circuit, the MOSFET itself is good, but the low resistance remains on the motherboard side.

PU8801 (SN1409049DPUR) measurements:

• Input pins 1, 2, 4, 6 and 7 measure very low to ground.
• Output pins measure normally (around 800-1200 in diode mode).
• PQ8801 source side measures normally (~600 diode mode).
• PQ8801 drain side is connected to the low-resistance rail.

At this point I am unsure whether:

1. 5.8-6 Ohms on +5VSUS is actually abnormal for this platform.
2. There is still another load connected to +5VSUS that I have not isolated.
3. The fault is somewhere in the +3VA_DSW / +5VSUS generation section around PU8701.
4. The original failure damaged an internal PCB layer.
5. I am chasing a normal resistance and looking in the wrong place.

Has anyone repaired this platform and knows what resistance is normally expected on +5VSUS with PU8701 removed?

Would you continue isolating loads from +5VSUS, or would you rebuild the complete PU8701 section first and continue troubleshooting after restoring +3VA_DSW and +5VSUS generation?

Any advice would be greatly appreciated.

Thank you.