fixing a dead psu

[finexo]

hi guys
i have a new corsaire cx 750 . i was runing 3 gpus with it (2 saphire amd r9 290 and 1 saphire amd hd 7950 ) after 15 days runing them for 24/24h the psu has stop runing
when i turn it on it just run for 5 to 10 min and then shutdown .
i have sent it to workshop he told me that all parts are okey . can any one help me

 

[dkulprit]

I would take one of the GPU's out. The AMD GPU's are power hogs. With it running for a few minutes before shutting down, I would either suspect that it is hitting a point where there is a major power draw and it is maxing out the PSU and causing it to shut down, or the AMD cards also run very hot so if you don't have proper ventilation it's possible that you are just overheating too.

But with 3 gpu's I am thinking it's the power draw. You didn't post your specs so I can't really do the calculations, but use this tool and throw in everything you have in your PC to see if maybe the power draw is just too high for a 750W.

http://www.coolermaster.com/power-supply-calculator/

EDIT:
With just 2 R9 290's without any other items in there, it is recommending 633w. So more then likely you are hitting your power limit.

Take the 7950 out.

 

[bignastyid]

You were overloading a lower quality PSU, I'm surprised it lasted 15 days. For your setup I recommend atleast a 1000w PSU, possibly more depending on the rest of the systems specs. I'm guessing you are using this is as a mining rig.

 

[finexo]

i have tried to run the psu with only one gpu but it shutdown after 20 min . now i know that i was overloading the psu . i just want to fix it now

 

[dkulprit]

i have tried to run the psu with only one gpu but it shutdown after 20 min . now i know that i was overloading the psu . i just want to fix it now

Overloading it like that probably blew capacitors. Unless you know board level repairs and can get your hands on the capacitors you are not going to do anything but damage it more. If I were you, you said it is new, Corsair has a decent warranty, I'd try to RMA it if I were you.

Just don't mention the whole overloading thing.

 

[finexo]

my waranty is avoid i have sent it to workshop they open it . i want to know the bad part so i will help the men in the workshop to fix it

 

[dkulprit]

The capacitors man. You blew the capacitors. The problem is that in a PSU you won't know which blew, or how many (there are a lot) so each would have to be desoldered from the PSU tested, find out how many need replacing, and then replaced and everything soldered back in. The cost of doing that is going to be higher then buying a new PSU.

Get a new PSU.

Try to warranty it anyways. The worst that will happen is that they will send it back.


ALSO FYI, not sure where you live. But in the US, that is not actually the case. They cannot VOID the warrantly or deny you a warranty because you or someone else opened it. You sure blew the warranty by overloading it. But they don't know that. They cannot void the warranty for you attempting to repair it yourself. They discourage people witht hose stickers, but it is illegal and can lead to fines or even a lawsuit if they do. It is called the Magnuson-Moss Warranty Act of 1975.

http://motherboard.vice.com/read/jailbreaking-iphone-rooting-android-does-not-void-warranty

 

[bignastyid]

i have tried to run the psu with only one gpu but it shutdown after 20 min . now i know that i was overloading the psu . i just want to fix it now

I highly doubt you can and for what it would cost to ship it to someone who could it would likely be cheaper and a whole lot faster buying a proper replacement.

 

[finexo]

i already both an enermax 1000 w psu today and its on the way . but i was looking for i way to fix it

 

[WyomingKnott]

Look on the bright side. The graphics cards and other components were not damaged. This is a Very Good Thing, as dying power supplies have been known to take other hardware with them.