Fried my old motherboard with brand new PSU

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datacenterguy

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Aug 31, 2017
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Last week I bought a brand new PSU (evga 700b1) as well as a gtx 1080. When installing the new PSU i plugged in a 4 pin molex connector and I did not notice that the shrouding was cracked allowing it to go in either way (I bought the motherboard used). I plugged it in backwards and when I turned the computer on I heard a pop and the PC would not turn on.

Now every time I attempt to turn on the pc it produces a burning smell.

Clearly my motherboard is fried but I'm unsure if the PSU is safe to use in my new motherboard ( i replaced the cpu and ram as well).

Do you guys think its ok to use? The PSU came with a power on self tester and it turns on fine.

Please advise I'm really worried I might damage my new motherboard.

Thanks!

Old setup:
I7 4820k
HD 7950
EVGA x79 Classified
Coolermaster 500w PSU

New Setup (haven't installed yet)
I5 7600k
MSI Z270 SLI
GTX 1080
Gigabyte 700 b1 psu
 
Solution
sirstinky
Rats. Sounds like there's a short in there somewhere. Likewise, I had forgotten that X79 EVGA board had an auxiliary Molex 12V plug on the board itself for running SLI. For one card, you don't need to use that plug.

For the PSU, it's 50/50 it might be okay, or it might be compromised, but still working. Really, not worth taking the chance when you can replace a PSU for $60-70. Beats replacing a board or a CPU, or graphics card that gets toasted by a bad PSU, right?
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HamBown81

HamBown81

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Aug 3, 2017
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Hard to say, it could still be damaged even if it turns on when shorted. That being said, it should be fairly well protected.

Personally, I would spend the bucks on a new PSU as insurance for my $1000+ system
 
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sirstinky

sirstinky

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Aug 17, 2012
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The Molex plug on the new power supply was broken, or were you trying to plug it into a Molex device (HDD, optical drive, PCIe socket with one of those Molex adapters?) What were you trying to plug a Molex connector into? The ATX 4/8 pin and 24 pin main ATX connections on the board are keyed to the plugs from the PSU, so it's really hard to plug it in incorrectly so from what you're saying, it might not be the board. It either popped something in the PSU or the part you connected backwards. Where does the burning smell come from? Do the PSU fans spin up when you turn it on? Unplug everything from the PSU and turn it on and see if you get smoke/burning smell. If it's a bad PSU, then don't plug it into anything.
 
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datacenterguy

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Aug 31, 2017
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It was a molex pci-e slot on the motherboard that was cracked. Normally they are slotted but since it was cracked I was able to plug it in easily. I had originally built the PC almost 3 years ago and I had no idea what I was doing. Last week I was tired and just wanted to put everything back the way it was. Looking back now I never even needed to use that slot lol.

I tried hooking up my old PSU to the mobo and it instantly smells of burnt near the 24 pin area
 
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datacenterguy

Prominent
Aug 31, 2017
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510
Upvote 0 Downvote
sirstinky

sirstinky

Distinguished
Aug 17, 2012
644
0
19,360
Rats. Sounds like there's a short in there somewhere. Likewise, I had forgotten that X79 EVGA board had an auxiliary Molex 12V plug on the board itself for running SLI. For one card, you don't need to use that plug.

For the PSU, it's 50/50 it might be okay, or it might be compromised, but still working. Really, not worth taking the chance when you can replace a PSU for $60-70. Beats replacing a board or a CPU, or graphics card that gets toasted by a bad PSU, right?
 
Upvote 0 Downvote
Solution
D

datacenterguy

Prominent
Aug 31, 2017
4
0
510
So i went ahead and took your guys' advice and replaced my PSU today. Bought a Corsair 650I. Works great no issues and my gtx 1080 survived. Unfortunately my hard drives didn't lol. Thank you for the help
 
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HamBown81

HamBown81

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Aug 3, 2017
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Better the drives than your GPU!
 
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sirstinky

sirstinky

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Aug 17, 2012
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Glad to help. Sorry your drives got bent. Beats having almost $1000 worth of hardware going sour!
 
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