Question Brand new PC short circuited w/ magic smoke after working perfectly; any idea what happened?

Aug 5, 2020
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so I built a new PC around 1 week ago, it worked fine for a day or so and everything was all good aside from the RGB fans on my new case not working, so I decided to open it up again and try to get the fans to work. The absolute most I could do was get one fan to light up, but none would spin, so the last thing I decided to try before giving up was flipping one 3pin fan cable on my mobo upside down because a friend suggested it (cable was not forced, it still fit fine), and that is when it decided to short circuit despite the PC powering on just a few minutes prior. The lights were not running clear on the GPU or mobo, they kept blinking and the PC overall refused to turn on. After powering the PSU off, I checked the inside of the PC for any debris, open cables etc. and then tried the power again after waiting for a bit. I reversed the cable back to where I had it before so now the PC was identical to how I had it prior to opening it back up. It ended up short circuiting again though this time it started making funny crackling noises and smelling heavily of burning plastic. Probably good to note the PSU also made a spark sound when being plugged in. Why did I continue I don't know. My PC is estimated at 220~250 watts and my PSU is an EVGA bronze 500W, so it's pretty evident my PSU should be able to handle it, but the next day I decided to take my GPU out anyways just to test if the PSU was being overpowered somehow. Once I did, I flipped the PSU power switch to on without turning on the entire PC and I immediately saw a line of smoke run from the first RAM slot, but there's no visual damage anywhere that I can see from taking it out. I'm thinking my PSU is just fried at the least so I bought a new one to test it out, but I'm unsure if other components are damaged. I called a repair guy but his price was the same as just getting a new PSU so I said <Mod Edit> it. Gonna take it apart today and see if there's any notable damage deeper inside and then hook up the new PSU next week. Every component in the computer is new except for the potentially busted PSU and also my GPU which are both around 2 to 3 years old. Any input on what you guys think happened? A few of my friends think the fan cables were either wired incorrectly or got fried somehow and affected my PSU.

https://pcpartpicker.com/list/XrDyYH

I may already have a plan on what I'm gonna try, but I'd love to hear some of your guys' input or advice or if what you think I'm doing is wrong. Thanks.
 
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Aug 5, 2020
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did you use the standoff for the motherboard to case?
When I was installing it I couldn't find the standoffs the case was supposed to come with. I asked a friend who is a technician (as this was my first build) and they said it would be fine as it's rarely an issue and that not all cases come with standoffs nowadays. So I screwed it in directly and it worked perfectly even whilst troubleshooting on the fans until I touched the one cable. I guess it definitely could be possible that the mobo came in contact with the case at that time, though I don't know how.
 

Turtle Rig

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Jun 23, 2020
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Oh man, Im so sorry for this happening to you. This is a very rare thing to happen. You smelled a nasty smell and smoke as well. Im hoping the PSU didn't damage your RAM and your video card. I don't think it killed the CPU. If the RAM slot area was jolted with a burn smell or smoke I can almost guarantee it killed the RAM with it. Butu don't quote me on that. A PSU can surely kill components if its faulty or a really cheap one or it blows up in your case. The first place to start it realizing that a short happened on this newly built rig of yours. Im betting the motherboard is toast the the simpler way of troubleshooting is going straight for the PSU but I have a sad feeling not only could the PSU be dead man walking but it took your components with it. The video card is usually the most expensive part of a computer so I hope it didn't fry it. To be positive about this try a brand new PSU. As for 250watt usage I highly doubt that as most newer builds take up on average 140watts on idle which also depends on the CPU and of course the video card. When you game this jumps way about 200 to 250watts like you said. Were talking 350 to 450watts unless you have a very low end GPU. I don't blame the PSU but I blame a shortage which can fry your stuff and I don't trust that the PSU was the problem to begin with. If you didn't see smoke or smell from the PSU area then you have most probably fried your motherboard and possible taken the RAM with it and hopefully not the GPU. I believe your CPU is fine tho. sighs :cautious:
 
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USAFRet

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When I was installing it I couldn't find the standoffs the case was supposed to come with. I asked a friend who is a technician (as this was my first build) and they said it would be fine as it's rarely an issue and that not all cases come with standoffs nowadays. So I screwed it in directly and it worked perfectly even whilst troubleshooting on the fans until I touched the one cable. I guess it definitely could be possible that the mobo came in contact with the case at that time, though I don't know how.
"rarely an issue", until it IS an issue.

Standoffs exist for a reason. If that particular case is supposed to have them...well, it is supposed to have them installed.
Your "friend who is a technician" sounds a bit clueless.
 
Aug 5, 2020
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"rarely an issue", until it IS an issue.

Standoffs exist for a reason. If that particular case is supposed to have them...well, it is supposed to have them installed.
Your "friend who is a technician" sounds a bit clueless.
Yeah... that's exactly what I told him when all of this happened. I asked if it could be the cause and he said that there's an extremely low chance that it is, telling me that it's practically impossible. I definitely regret listening to him if this ended up being it.
 
Aug 5, 2020
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Oh man, Im so sorry for this happening to you. This is a very rare thing to happen. You smelled a nasty smell and smoke as well. Im hoping the PSU didn't damage your RAM and your video card. I don't think it killed the CPU. If the RAM slot area was jolted with a burn smell or smoke I can almost guarantee it killed the RAM with it. Butu don't quote me on that. A PSU can surely kill components if its faulty or a really cheap one or it blows up in your case. The first place to start it realizing that a short happened on this newly built rig of yours. Im betting the motherboard is toast the the simpler way of troubleshooting is going straight for the PSU but I have a sad feeling not only could the PSU be dead man walking but it took your components with it. The video card is usually the most expensive part of a computer so I hope it didn't fry it. To be positive about this try a brand new PSU. As for 250watt usage I highly doubt that as most newer builds take up on average 140watts on idle which also depends on the CPU and of course the video card. When you game this jumps way about 200 to 250watts like you said. Were talking 350 to 450watts unless you have a very low end GPU. I don't blame the PSU but I blame a shortage which can fry your stuff and I don't trust that the PSU was the problem to begin with. If you didn't see smoke or smell from the PSU area then you have most probably fried your motherboard and possible taken the RAM with it and hopefully not the GPU. I believe your CPU is fine tho. sighs :cautious:
I got a chance to take out everything from the computer, and visually, it appears to be fine from almost every aspect, but I guess that doesn't mean it isn't damaged. The RAM looks good, so does the GPU, but I agree I'm pretty sure at this point it's obvious that the mobo is fried from this. I think I decided to try and replace the case, PSU, and mobo, hoping that this short circuit didn't take anything else with it like you said. I think it's a risky move to troubleshoot with just a new PSU in case the mobo is fried. Everytime I troubleshoot this thing it just keeps getting worse, so I'm gonna try to replace as much as I can and go with it. I posted on another website and a guy told me it's possible that I misplugged the 3pin fan cable, and looking at my mobo's setup, it seems like a reasonable narrative. It could be an issue with the standoffs as well, but I think that's less likely though I'm surely not ruling it out.
 

Andrew Fox

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When I was installing it I couldn't find the standoffs the case was supposed to come with. I asked a friend who is a technician (as this was my first build) and they said it would be fine as it's rarely an issue and that not all cases come with standoffs nowadays. So I screwed it in directly and it worked perfectly even whilst troubleshooting on the fans until I touched the one cable. I guess it definitely could be possible that the mobo came in contact with the case at that time, though I don't know how.
RIP to your motherboard, i've killed two DFI LanParty boards in my youth by having standoffs in the incorrect spot and shorting them out. Live & learn I guess. Hopefully you can just take the board back to where you got it and say it was a DOA faulty board, they probably can't tell what caused the damage and will exchange it for you. Make sure you put standoffs in the correct spots and don't have any where they don't line up to the holes. Never install a board without standoffs!

I decided to try and replace the case, PSU, and mobo, hoping that this short circuit didn't take anything else with it like you said
Why would you need to replace the case? Just install standoffs into the proper spots and you'll be sweet. The PSU is most likely fine too. Just replace your motherboard and you should be okay. (if you saw the magic smoke next to the RAM then maybe the RAM might need replacing too though)
 
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DSzymborski

Champion
Moderator
Hopefully you can just take the board back to where you got it and say it was a DOA faulty board, they probably can't tell what caused the damage and will exchange it for you. Make sure you put standoffs in the correct spots and don't have any where they don't line up to the holes. Never install a board without standoffs!
Please don't advise people to commit criminal consumer fraud.
 
Aug 5, 2020
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"and I immediately saw a line of smoke run from the first RAM slot "

Thats not a misconnected fan.
Well the misconnected cable could have caused the mobo to short couldn't it have? Having power sent to the wrong insertions with the wrong connector? In his case that's what he said happened atleast.
 
Aug 5, 2020
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RIP to your motherboard, i've killed two DFI LanParty boards in my youth by having standoffs in the incorrect spot and shorting them out. Live & learn I guess. Hopefully you can just take the board back to where you got it and say it was a DOA faulty board, they probably can't tell what caused the damage and will exchange it for you. Make sure you put standoffs in the correct spots and don't have any where they don't line up to the holes. Never install a board without standoffs!


Why would you need to replace the case? Just install standoffs into the proper spots and you'll be sweet. The PSU is most likely fine too. Just replace your motherboard and you should be okay. (if you saw the magic smoke next to the RAM then maybe the RAM might need replacing too though)
Because even when the computer worked properly, no matter what I did the RGB fans refused to work. The most I could do was power only one of them on with lights. None of them even spun, and I did have all of the fan cables connected initially that I was supposed to. In the end whether the case was damaged or not I decided it felt like too much trouble, so I returned it with everything it came with. Thank you though, I definitely won't make this mistake again if the standoffs do turn out to be what caused the issue here.
 

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