MSI GS76 STEALTH 11UG No Power (Please tell me I didn't kill my baby!)

[Digighost]

Hello Everyone Please bear with me as I'm not very experienced in electronics and board repair but I think with a little help from you experienced guys I can get this done. I do have a tech background and I believe I have all the needed equipment to complete the task at hand.

A week ago my MSI GS76 STEALTH 11UG (board MS-17M11) No easy way to say this I think I may have killed my baby. What had happened was My ALFA External Wifi was not being recognized because it needed more power than my machine could output. After researching the issue I found out that using a powered USB hub should fix the issue. Somehow I don't know exactly how there must have been a surge and my computer went dead.

I opened it up and found a chip had blown next to the USB port so I removed it. However, that chip I do not think is the issue here. I'm going to include some pics and if you guys who are more knowledgeable than me could let me know if I'm correct in my assumptions or maybe an idiot who doesn't want to admit the possibility that I murdered my baby. Just looking for honest opinions.

The first image is the location of the blown component and a arrow pointing to its twin on the other usb port.



Next, we have some voltage readings I took leading me to believe there is a short on the main power rail. As you can see voltage is at 20.2v up until either the cap or mosfet gate not sure which comes first. But The MOSFET gate reads 8.6v which doesn't look correct to me. Also, the bottom of the capacitor is reading 8.6v as well while the top reads 20.2v. This is a short right sorry for my ignorance I just don't want to remove something that doesn't need to be removed.



I appreciate all of your time thanks in advance!

Oh Yea, I also attached the spec sheet for the MOSFET if needed.

[diif]

Re: MSI GS76 STEALTH 11UG No Power (Please tell me I didn't kill my baby!)

You don't mention what you exactly did. Powered USB is mentioned then dead PC, how was it connected ?

[Digighost]

Re: MSI GS76 STEALTH 11UG No Power (Please tell me I didn't kill my baby!)

Yes, it was connected When the surge happened,

[mon2]

Re: MSI GS76 STEALTH 11UG No Power (Please tell me I didn't kill my baby!)

The referenced mosfet is a P-channel type. This type does require the gate to be at a lower voltage than the voltage being passed between source and drain pins to enable. That is, someone on the board wants to enable this mosfet and the mosfet is enabled so the voltage is present on both sides of the mosfet as measured.

The blown chip was a USB load switch. This load switch is acting like a solid state relay that will current limit the voltage on the USB vbus pin. If the current draw is exceeded, it should shut off and report this fault to the upstream USB host controller = PCH IC. Next time, do practice on a donor board and use lots of flux and high heat but low air pressure to allow the solder to melt. When it does, the chip will swim in the solder bath and you can then remove the part with tweezers. Lots of patience. Some of the load switch pads have been lifted off the pcb. At this time, this is not the show stopper but the linked USB port connector will not be functional.

Share the top side markings of the other load switch that is nearby so we can find a datasheet and it's pin out.

[Digighost]

Re: MSI GS76 STEALTH 11UG No Power (Please tell me I didn't kill my baby!)

The referenced mosfet is a P-channel type. This type does require the gate to be at a lower voltage than the voltage being passed between source and drain pins to enable. That is, someone on the board wants to enable this mosfet and the mosfet is enabled so the voltage is present on both sides of the mosfet as measured.

The blown chip was a USB load switch. This load switch is acting like a solid state relay that will current limit the voltage on the USB vbus pin. If the current draw is exceeded, it should shut off and report this fault to the upstream USB host controller = PCH IC. Next time, do practice on a donor board and use lots of flux and high heat but low air pressure to allow the solder to melt. When it does, the chip will swim in the solder bath and you can then remove the part with tweezers. Lots of patience. Some of the load switch pads have been lifted off the pcb. At this time, this is not the show stopper but the linked USB port connector will not be functional.

Share the top side markings of the other load switch that is nearby so we can find a datasheet and it's pin out.

Thanks for the reply, I agree with everything you said, and have gotten a donor board and have been practicing. Impatience was my enemy there. I figure I will have to repair the pads if I want the USB to work in the future but as of now, that is secondary.

What do you think about the capacitor having the 8.6v on what to me looks like the negative side does this indicate a short? I will post the number of the USB load switch in a few minutes.

[Digighost]

Re: MSI GS76 STEALTH 11UG No Power (Please tell me I didn't kill my baby!)



Looks like X228 G547I1

[Digighost]

Re: MSI GS76 STEALTH 11UG No Power (Please tell me I didn't kill my baby!)

At this point if I use a power supply to try and turn it on I'm getting some readings that my instinct says could be a shorted SIO chip. I hope that is not the case because the fastest I can find shipping for one of those is up to six weeks and I can't afford to be that long without my computer so I might end up having to buy a new motherboard which honestly sucks.



5v, 3.3v, 1.8v rails are all online to add to the information available. I will do further investigation and get more readings to add very soon as well.

[Digighost]

Re: MSI GS76 STEALTH 11UG No Power (Please tell me I didn't kill my baby!)

Anyone had similar issues who could bring some clarity to what my next steps should be?

[mon2]

Re: MSI GS76 STEALTH 11UG No Power (Please tell me I didn't kill my baby!)

If the exact schematic for this unit is not available, start with the basics.

Use your power supply if it is able to deliver the current and if it can communicate like the original power adapter.

That is, some motherboards demand a proper single wire communication to authenticate the power adapter (ie. Dell). HP will check for a special low voltage for the same reason on a PS_ID pin.

After mating the power supply, check each and every power inductor for its voltage to ground. Do attempt to power up. At ~100mA current draw, the logic board is not powered up. Each inductor is linked to a local power supply (switching buck regulator that creates a local power rail).

[Digighost]

Re: MSI GS76 STEALTH 11UG No Power (Please tell me I didn't kill my baby!)

If the exact schematic for this unit is not available, start with the basics.

Use your power supply if it is able to deliver the current and if it can communicate like the original power adapter.

That is, some motherboards demand a proper single wire communication to authenticate the power adapter (ie. Dell). HP will check for a special low voltage for the same reason on a PS_ID pin.

After mating the power supply, check each and every power inductor for its voltage to ground. Do attempt to power up. At ~100mA current draw, the logic board is not powered up. Each inductor is linked to a local power supply (switching buck regulator that creates a local power rail).

thank you for the reply ill do that and yes it does seem to pair with my supply just fine.

Once the Power Supply is connected it goes to 20.2v 118 mA

After pushing what i believe is the power button it drops to 20.2v 25 mA for 0.5 secs then back to 118 mA

[Digighost]

Re: MSI GS76 STEALTH 11UG No Power (Please tell me I didn't kill my baby!)

Here are my inductor voltages to the ground.

[Digighost]

Re: MSI GS76 STEALTH 11UG No Power (Please tell me I didn't kill my baby!)

UPDATE: So i just tried to plug the battery in while paired to my power supply and it seems to be charging the battery. Im getting charging light and its drawing @ 1Amp

So at this point, I have a couple of questions i hope some of you can answer.

1. If the Super IO chip was bad would my laptop be able to charge the battery?

2. What is the best method I should use to find out why Im getting 0v readings in my upper inductors?

Thanks in advance.

[ResoluteHawk]

Re: MSI GS76 STEALTH 11UG No Power (Please tell me I didn't kill my baby!)

So does the laptop turn on when you press the power button with the battery connected?

1) Yes and No. Your Super IO could be partially shorted and still perform basic functionalities.

2) The main possibilities for 0V on the CPU inductors are:
=> a) laptop is not powered on, hence no CPU voltage
=> b) a straight 0 Ohm short to ground on the CPU inductors
=> c) the CPU PWM driver that opens the cpu mosfets isn't working correctly, even when the laptop is on, causing a cold CPU.
=> d) partially shorted PCH/chipset. Even when power is plugged in and the laptop is off, it may have a heat spot.

Check your resistance to ground (power and battery unplugged) on each of the CPU inductors and on the input current sense resistor (DC jack and directly to the right of it after those two mosfets).
Also, check resistance to ground on Pin #8 of the BIOS/UEFI chip as it ties directly into the PCH. More times than not, low resistance on Pin #8 of the BIOS/UEFI chip indicates a shorted PCH, and this could also cause a charge light with no power on. BIOS chip looks to be just to the right of the chipset, below the 1.8V inductor, and bottom left below the memory modules.
When you locate the BIOS/UEFI IC, Pin #8 is going to be on the top left (from looking at the photo in Post #11).

[Digighost]

Re: MSI GS76 STEALTH 11UG No Power (Please tell me I didn't kill my baby!)

So does the laptop turn on when you press the power button with the battery connected?

1) Yes and No. Your Super IO could be partially shorted and still perform basic functionalities.

2) The main possibilities for 0V on the CPU inductors are:
=> a) laptop is not powered on, hence no CPU voltage
=> b) a straight 0 Ohm short to ground on the CPU inductors
=> c) the CPU PWM driver that opens the cpu mosfets isn't working correctly, even when the laptop is on, causing a cold CPU.
=> d) partially shorted PCH/chipset. Even when power is plugged in and the laptop is off, it may have a heat spot.

Check your resistance to ground (power and battery unplugged) on each of the CPU inductors and on the input current sense resistor (DC jack and directly to the right of it after those two mosfets).
Also, check resistance to ground on Pin #8 of the BIOS/UEFI chip as it ties directly into the PCH. More times than not, low resistance on Pin #8 of the BIOS/UEFI chip indicates a shorted PCH, and this could also cause a charge light with no power on. BIOS chip looks to be just to the right of the chipset, below the 1.8V inductor, and bottom left below the memory modules.
When you locate the BIOS/UEFI IC, Pin #8 is going to be on the top left (from looking at the photo in Post #11).

Thank You for the reply the #8 pin on BIOS chip is reading 78Ohms to ground.

[Digighost]

Re: MSI GS76 STEALTH 11UG No Power (Please tell me I didn't kill my baby!)

So does the laptop turn on when you press the power button with the battery connected?

1) Yes and No. Your Super IO could be partially shorted and still perform basic functionalities.

2) The main possibilities for 0V on the CPU inductors are:
=> a) laptop is not powered on, hence no CPU voltage
=> b) a straight 0 Ohm short to ground on the CPU inductors
=> c) the CPU PWM driver that opens the cpu mosfets isn't working correctly, even when the laptop is on, causing a cold CPU.
=> d) partially shorted PCH/chipset. Even when power is plugged in and the laptop is off, it may have a heat spot.

Check your resistance to ground (power and battery unplugged) on each of the CPU inductors and on the input current sense resistor (DC jack and directly to the right of it after those two mosfets).
Also, check resistance to ground on Pin #8 of the BIOS/UEFI chip as it ties directly into the PCH. More times than not, low resistance on Pin #8 of the BIOS/UEFI chip indicates a shorted PCH, and this could also cause a charge light with no power on. BIOS chip looks to be just to the right of the chipset, below the 1.8V inductor, and bottom left below the memory modules.
When you locate the BIOS/UEFI IC, Pin #8 is going to be on the top left (from looking at the photo in Post #11).

Thank You for the reply the #8 pin on BIOS chip is reading 78 Ohms to ground.

[ResoluteHawk]

Re: MSI GS76 STEALTH 11UG No Power (Please tell me I didn't kill my baby!)

Ok. There's a good chance that your PCH is toasted, or a trace underneath your PCH is shorted.

Either way, the only way to find out if this short goes away is going to be removing your PCH.

[Digighost]

Re: MSI GS76 STEALTH 11UG No Power (Please tell me I didn't kill my baby!)

Ok. There's a good chance that your PCH is toasted, or a trace underneath your PCH is shorted.

Either way, the only way to find out if this short goes away is going to be removing your PCH.

Thank You for your reply. Im going to have to research the pch and figure out my next steps. At risk of sounding like a complete moron. The pch is the chip to the right of the bios chip correct? Is it just a single chip? And how big of a deal would that be?

Wanted to include a big thanks for your help I know everyone is busy with their own stuff and I really appreciate you taking the time to looking at my issue

[Sephir0th]

Re: MSI GS76 STEALTH 11UG No Power (Please tell me I didn't kill my baby!)

It is for most of the technicians a impossible "deal" and regarding the history it probably won't be a problem with the tracks

[Digighost]

I wanted to give you all an update on the issue I've been dealing with. Sorry for the delay; I fell behind on a project because of this problem, and once I fixed it, I got caught up in work and forgot to reply.

First, I replaced the PCH, but it still didn't work. I thought I might have either broken it while trying to fix it or replaced the wrong part.

After watching a lot of videos, I figured out that the issue was actually the Super IO chip. I ordered a new one from China, which arrived about a week and a half later.

While waiting for the new chip, I desoldered almost every component from every circuit board I could find. I fixed the traces that I had initially messed up in my haste and installed a new USB port to prepare.

When the new Super IO chip arrived, I replaced the old one, and it worked!