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Old 08-13-2021, 08:24 AM   #1
taxxin
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Default Zotac gtx-750ti 2gb vcore short

Dear Members,

I would like some of you to share your experience with Vcore shorts to determine whether or not this card is salvageable.

We have a 750ti here with a vcore short, it does not have an external atx power connected on this model so i can only assume that it is a 75w max from the pcie slot only.

On the 12v rail there is a dead short, almost 0 ohms, i voltage injected it to confirm and yes whatever voltage you put into it is what is being directly fed to the GPU.

Do you think that this GPU could still be operational if i repair the power circuit. I could replace all mosfets and driver uP1641P It should be fine again, however im not sure if the PSU short protection would have been enough to protect the GPU chip from a blast of 12v power?

What do you think would be the smartest course of action??
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Old 08-14-2021, 11:56 AM   #2
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Default Re: Zotac gtx-750ti 2gb vcore short

Well that would depend on what was causing the short. I while ago i looked at three GTX780

Only one had a GPU Vcore short and that turned out to be an MLCC capacitor - so it does happen. Problem is finding the short circuit component - in my case I could only spot it by removing the GPU and finding the short still there. Injecting a voltage to see what got hot before didn't help due to the fact with the GPU load present I could not inject enough current from my PSU
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Old 08-25-2021, 02:11 PM   #3
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Default Re: Zotac gtx-750ti 2gb vcore short

Quote:
Originally Posted by dicky96 View Post
Well that would depend on what was causing the short. I while ago i looked at three GTX780

Only one had a GPU Vcore short and that turned out to be an MLCC capacitor - so it does happen. Problem is finding the short circuit component - in my case I could only spot it by removing the GPU and finding the short still there. Injecting a voltage to see what got hot before didn't help due to the fact with the GPU load present I could not inject enough current from my PSU
Thank you for the input Rich, I there are only 2 phases on this card so i could probably desolder all 6 mosfets to check if the short is gone it should isolate the power circuit from the GPU. Im thinking its most likely to be a faulty mosfet and driver shorting drain to source
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Old 08-26-2021, 05:28 PM   #4
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Default Re: Zotac gtx-750ti 2gb vcore short

I've had good luck with older cards (a GeForce 7600 and a GeForce 9400) surviving a shorted upper Vcore MOSFET. In both cases, the lower Vcore VRM MOSFET latched On and tripped the PSU short-circuit protection, thus saving the card.

That said, I don't know if newer cards are as rigid and could take such abuse. But given the current situation with video cards around the world right now, perhaps give your GTX 750TI a try if the MOSFETs/drivers aren't too expensive or hard to find. Moreover, like Rich mentioned, it could also just be a shorted ceramic cap that caused the fault... in which case, the GPU Vcore should definitely have survived.
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Old 09-06-2021, 06:55 AM   #5
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Default Re: Zotac gtx-750ti 2gb vcore short

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Originally Posted by momaka View Post
I've had good luck with older cards (a GeForce 7600 and a GeForce 9400) surviving a shorted upper Vcore MOSFET. In both cases, the lower Vcore VRM MOSFET latched On and tripped the PSU short-circuit protection, thus saving the card.

That said, I don't know if newer cards are as rigid and could take such abuse. But given the current situation with video cards around the world right now, perhaps give your GTX 750TI a try if the MOSFETs/drivers aren't too expensive or hard to find. Moreover, like Rich mentioned, it could also just be a shorted ceramic cap that caused the fault... in which case, the GPU Vcore should definitely have survived.
Thank you for the input i think that this GPU uses the same mosfets a 660ti that i have here, i guess i will start with removing and checking them one by one, at least we will have a better idea of what it is that is causing the short.
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