Author Topic: GTX 980 Graphics Card MOSFET  (Read 1249 times)

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Offline alicexyamasaki

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GTX 980 Graphics Card MOSFET
« on: January 28, 2019, 01:48:35 am »
Hi All,

I have never attempted a graphics card repair before so I'm not sure really what to do. All I am sure of is that one of the power MOSFETS are broken (as shown in the picture) but I'm not sure as to what the primary cause was or how to go about finding it. I have searched on the internet for a schematic to try to identify different components but my luck has been very dry doing so. Although, I am pretty certain that the broken MOSFET is the 4C10N as it is in the array. What would be the best to go about for this repair and what could I do to try to identify the root cause of the initial problem?

If it helps, it is a GTX 980 ACX 2.0, board id:n30233.

Many thanks in advanced!
 

Offline wraper

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Re: GTX 980 Graphics Card MOSFET
« Reply #1 on: January 28, 2019, 02:19:51 am »
It may be different. Might be just this single mosfet dying by itself, it might also taken other mosfets with it. It might failed because of faulty controller, or opposite - damaged controller when failing. In best case scenario, replacing single mosfet will fix the thing.
 

Offline Johnny10

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Re: GTX 980 Graphics Card MOSFET
« Reply #2 on: January 28, 2019, 03:45:35 am »
What is oozing out of that chip?

Looks like it was heated enough to melt solder on 6 pins.
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Offline mariush

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Re: GTX 980 Graphics Card MOSFET
« Reply #3 on: January 28, 2019, 06:34:16 am »
Desolder the chip that looks blown up.
Use multimeter to measure continuity between gate, drain and source pads of the other mosfets to determine if they're shorted or not
Measure continuity between input and ground of the vrm controller for a basic check to see if controller is shorted / dead.

Measure resistances between mosfet gates and the vrm controller (or the phase doublers), see if there's anything shorted between those..

If you're lucky, the video card used pairs of mosfets, in order to reduce heat on the mosfets, so if just that mosfet is dead, the video card may work and run (at least for testing purposes) with just one mosfet out of the pair, on that vrm phase.

These videos are in russian, but maybe you can follow the tests he makes to see if other parts are faulty :

mosfet dead on one phase of the vrm, took the controller with it :







and a bit unrelated, but cool how he detects the memory chips are shot



The whole channel is worth bookmarking if you're into repairs

 
 

Offline alicexyamasaki

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Re: GTX 980 Graphics Card MOSFET
« Reply #4 on: January 28, 2019, 09:51:14 am »
Haha I hope it is the best case scenario. Although, the lights still turn on and the fans click a bit so they definitely still get power; leading me to think that maybe the controller is okay? I'm not sure!
 


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