Alienware 18, Nvidia GTX 880m presumably shorted

[GTAVC16]

Hi guys!

I'm in need of some support so I can try to fix my laptop/gpu.
While I am a cerified automotive mechatronic, I have only basic understanding of electronics repair and identification.
I'd like to identify the issue and replace the specific component myself to learn about electronics and expand my skills a bit.
No better time than now, when my laptop, Alienware 18 from 2013, shut down when playing and refused to start again.
I know about electric diagnostics in and about cars, but I've never dabbled with electronics.
However, I know that I should not willy nilly try to stick my multimeter at everything in my card to measure resistance. :-P
In my opinion one should only take a measurement if one knows what kind of result is expected.

What am I working on?

I have an almost ancient gaming laptop, It is an Alienware 18 R1 built around 2013-ish.
There is some confusion about their naming conventions, it is not a m18 and also not a M18x. Those are different gaming laptops and most of the guides I found were about those. :-/
CPU: Intel 4930MX i7 (not 100% sure about that)
GPU: 2x Nvidia GTX 880m with SLI
Motherboard: VAS10 LA-9332P
Power Supply: Original AC/DC adapter, output rating: 19,5V, 16,9A

What happened?

While gaming, the laptop suddenly shut down and refused to start again.
The current weather is quite hot, so I presumed that it shut down due to overheating.
This never happened before and I always take measures to insure propper airflow for the fans. (Laptop on a hard table, steering exhaust away from intake.)
After leeting it cool cown a bit, it still refused to start.
This is when I found out that the green LED from the power supply brick has shut down, indicating no power due to some sort of protection mechanism.
Unplugging the PSU from both the laptop and the wall, and plugging it back in to the wall socket, the green LED lights up again.
However, it shuts down again as soon as I plug it back to the laptop.
There is a click at the laptop and a slight smell ozone, indicating some sort of arcing.

My diagnostic procedure

I looked up a disassembly video on youtube and disassembled my laptop to check for my first presumption about the issue, a damaged charging port.
This is/was a high-end gaming laptop and could be a common issue.
However, I could not find any kind of damage around the charging area, no burn marks, no loose parts, nothing.
When plugging in the board to the PSU, the light stays on, indicating that the issue is currently not present.

Getting in deeper in my rabbit hole, I found that the primary graphics card tends to fail often, so I unplugged the PSU and mounted the primary Nvidia 880m back on. Now, when connecting the PSU, it shuts off again.

To be sure that it is related to this GPU, I did the same with the CPU and secondary GPU and the power stays on.

The primary GPU seems to be the issue, but what now?

I've taken a good look at the GPU and did not find any damage or burn marks.
I'd like to take some measurements, but I only have experience with measuring electrics, not electronics, so I need some kind of visual guide for where to measure and what values to expect.
I was unable to find any schematics for the GTX 880m.
Some help would be greatly appreciated.

I have a multimeter on hand, and I'll put pictures of the GPU in the attachments.

[Sephir0th]

Re: Alienware 18, Nvidia GTX 880m presumably shorted

The GPU is quite old and the death was just a question of time. Most likely a dead Core where you actually can't do anything.
However, I'm not sure whether you're in the right section here at all since we're more talking about a socketed GPU than a Laptop motherboard.

However, you have a second, working GPU so you could at least compare resistance measurements from the various inductors to start with and also take voltage measurements by any chance?

But clarify first: Does the laptop not start at all with the suspected faulty GPU, which would lead to a failed High-Side or is it"just" shutting down after a few seconds?

[GTAVC16]

Re: Alienware 18, Nvidia GTX 880m presumably shorted

Thank you for your answer, Sephir0th!

It doesn't start at all when the faulty GPU is connected, both with and without connected battery.
No beeping, no lights, no booting, the same lifesigns like a DMV employee.
The PSU trips as soon as I plug it into the board with the faulty (primary) GPU connected.
The PSU does not trip if both CPU and secondary GPU are connected.
When I push the power button, nothing happens. I tried both short and long presses.

What pins would I need to compare to get further along with what is wrong with the card? Forgive me my lack of knowledge on that part.
Even if the card is unsalvagable, I'd still like to learn as much as I can.

In addition, placing the primary GPU in the slot of the secondary GPU yields the same, the location of the problem seems to be this primary GPU.

[Sephir0th]

Re: Alienware 18, Nvidia GTX 880m presumably shorted

That's probably a high-side short. Don't test with power anymore. The main power rail of the mainboard is probably shorted with one of the power rails related to the primary GPU, as long as it is present on your board.
So i don't know your skills... Are you able to identify the main power rail at the GPU and look for a internal shorted Mosfet. But pay attention, there are also Mosfets connected to GND and the resistance of the load is likely very low. So there might appear Mosfets as shorted, although they are not.

[ktmmotocross]

Re: Alienware 18, Nvidia GTX 880m presumably shorted

mostly shorted some mosfet on main gpu rail. or shorted capacitor.

measure resistance between two thick pads on mxm conector if u have resistance under 1ohm, u have short to ground/shorted lowside mosfet or capacitor/. if u have resistance 2-10ohm u have shorted one of high side mosfet

[GTAVC16]

Re: Alienware 18, Nvidia GTX 880m presumably shorted

I just took some measurements and found 0.7 Ohm on the bottom side and 0.1 Ohm at the top side.

How can I identify the power rail to find the damaged parts?

[Sephir0th]

Re: Alienware 18, Nvidia GTX 880m presumably shorted

That's the point: you need to find out what is PLUS and what is GND. Either from Injecting or from logical conclusions. Share a picture with your measurements included please.

[GTAVC16]

Re: Alienware 18, Nvidia GTX 880m presumably shorted

I'm sorry if I'm being incredibly dense right now.
Where exactly do I need to stick my multimeter?
I've tried to figure this out since yesterday, but my lack of electronics experience shows. :-/

[dellxps15]

Re: Alienware 18, Nvidia GTX 880m presumably shorted

short on the 19 volt line.

this has removable cpu ?

if so remove gpu and cpu. check if 19volt still shorted (should be still shorted).

then inject 1 volt on 19volt like and check what get hot. probably a caps on the back of cpu or some mosfet or so...

had one alienware with dead caps and another one with dead mosfet.

not mainly it measns cpu and gpu are dead. expecially if u can remove them

put 1 volt on the big resistor close to power jack . it's very big so u can miss that one. before ofcourse with multimeter in diode mode check if it's shorted or not.

red probe on gnd (usb metal, other metal on mainboard) and black on that resistor (both side to be sure). then we procede further.

[GTAVC16]

Re: Alienware 18, Nvidia GTX 880m presumably shorted

Can you please take my screenshot and put some arrows on the points I have to take measurements?
This is literally my first time dabbling with electronics, i have absolutly no clue what components you mean with 19 line.
I'm sorry, but it isn't obvious to me, but I'd like to learn, how can I identify this 19 volt line?

[dellxps15]

Re: Alienware 18, Nvidia GTX 880m presumably shorted

measure are on the mainboard not vga.

also as i write: without cpu and gpu (if cpu is removable) psu green light still goes off ?

[GTAVC16]

Re: Alienware 18, Nvidia GTX 880m presumably shorted

The psu green light only shuts off if the primary GPU is installed.
The light stays on, if the CPU and secodary GPU is installed.
The light shuts off, if the primary GPU is installed in the secondary slot.

My conclusion is that my laptops primary GPU has a short somewhere, and thanks to the Sephir0th and ktmmotocross whom helped me tremendously, I took some basic measurements and found out that I have >1 Ohm at the power connectors of this GPU, indicating either a short to ground, damaged lowside MOSFET or a damaged capacitor.

Now my task is to find the damaged parts, but I have no idea where to measure.
I googled the parts number and found some MOSFET schematics, but the order of the pins somehow don't translate to the thing I have in front of me.
Also, what kind of measurement am I looking for? Measure everything to ground, across the MOSFET?
I really have no clue what is expected of me.

[dellxps15]

Re: Alienware 18, Nvidia GTX 880m presumably shorted

ive attached picture of one 880m i had in my old alienware. put multimeter in diode mode and red probe on rec spot. then one by one change the back probe to the 5 green spot and read value u have each spot. then measure also blue spot.

post results.

[GTAVC16]

Re: Alienware 18, Nvidia GTX 880m presumably shorted

Thanks for your help, dellxps15!

I've taken the measurements and everything comes up with 0.01V.
One of your pictures does not have any marking, is this on purpose or should I take some measurements from there, too?

[dellxps15]

Re: Alienware 18, Nvidia GTX 880m presumably shorted

edit checked on a vga i have here. blue spot is gnd, so it's normal to have 0,001.

do you have lab psu ?

[GTAVC16]

Re: Alienware 18, Nvidia GTX 880m presumably shorted

Sadly no, I might have one at work that I can use, but I doubt it.

[ktmmotocross]

Re: Alienware 18, Nvidia GTX 880m presumably shorted

remove that 4 upper mosfets and check it

[craig2991]

Hello Sir, were you able to fix/turn on your lap top? I was having the same issue with my Alienware 18. Mine won't turn on and the AC adapter LED turns off when plugging into laptop. Reading the threads says the system must have a short. I don't think the ac jack cause the problem after carefully inspect the charging area. I suspet one of the graphic card is broken. I'm trying to dettach the both graphic cards to see if I can turn it on. Before I do that, just wanted to check with you to see if you have updates on this since we have similiar model and issue. Thank you!