Question My PSU/PC Doesn't boot when it's plugged in to the mobo (24 Pin Only, The rest seems to work)

bigbobsmith1968

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Hello, recently my pc stopped turning on, then it would turn on again then it just went off permanently.

To me it seemed like a PSU issue, so I bought a new psu which happened to come with a tester. So tested my new PSU and it worked well.
Then I finally realized the simple idea that I should also test my old PSU. Then when I plugged the 24Pin into the tester and turned on the old PSU and the fans powered up. So I went, "Hm maybe I should plug everything back in" plugged everything back into the mobo and the PSU wouldn't power on.

I am guessing this is a broken 24Pin connector on the MOBO side.
If so could anyone confirm my idea, and if not could someone please help me out.

Thank you all for the help in advance!!! :)

Could it also be maybe the CMOS Battery?
 
Last edited:

Karadjgne

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Tester is almost a gimmick. The only thing it'll do is show a psu has working rails, what it does not do is show how much those rails will work. They can give a false sense of security.

It's like getting into a car and dome light works, and the ignition dings. Doesn't tell you if the car will start, how it will run, if the transmission actually works or if it'll blow up when you floor the gas pedal.
 
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ajaz1986

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Have you tried re-seating the ramsticks or pulling out the CMOS battery and jumping the pins to reset CMOS settings? If you have another mobo, would be good to swap the CPU/RAM over and see if it boots up on another mobo.
 

bigbobsmith1968

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I have tried Re-Seating The Ram, I haven't tried pulling the CMOS Battery, Or jumping the pins. Sadly I don't have another MoBo I just tried the ram in another pc. It acted strange... but I also did have a set of RAM I know works in my pc and it still wouldn't boot. Tomorrow I will try everything else that I can do. ty for the help so far!!! :)
 

bigbobsmith1968

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I still haven’t pulled the CMOS battery but now I am stuck… I re-Built my whole PC still nothing! I tried jumping the pins, re-re doing everything, with a new PSU! Could it be a dead MOBO?
 

bigbobsmith1968

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Rebuilt my whole PC. I didn’t re-use any cables minus my HDD and SSD sata cables but those don’t connect to the PSU and came with the MOBO. Jumped the pins… I still have no idea
 

Karadjgne

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So what exactly is the issue? Is there any power at all to the motherboard or anything and it just won't boot or is there totally no power at all. If totally no power and jumping the pwr_on pins does nothing I'd be inclined to believe the problem is the motherboard itself.

I'd breadboard it. Pull it out of the case and hook up nothing except 1 stick of ram in A2, cpu, cpu cooler and the 24pin/eps power cables. No gpu, no drives, no monitor, no extras, just the absolute basics. If it doesn't cycle then the motherboard is toast. If it does, then start adding 1 component at a time, all outside of the case, rebooting in between. Do so until it stops.
 
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bigbobsmith1968

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Ok!!! I will try this!!! I am guessing my MOBO is just fried which sucks! I don’t have an extra. Yeah, no power at all, no cycling, nothing at all :( But I will Breadboard it later today!
 

bigbobsmith1968

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No bulging or blown caps! Still doesn’t boot up, (I did leave it in the case, because it is a ton of work to get it out of that case) unplugged everything except the essentials! One interesting thing is that I noticed is that a couple of the stand-off screws were missing. I don’t know if me forgetting to screw a couple screws could break my mobo. Any other ideas? Thanks for all the help!!!

Edit: also no burn spots
Also I forgot unplug the SATA from the PSU is that worth a try or no? I unplugged the other end to the HDD and SSD
 

Karadjgne

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No, forgetting to screw a couple of standoffs doesn't hurt anything. Unless those standoffs were in a different spot to start with and you didn't move them to the correct locations to match the motherboard mounting holes. In that case, you'd have standoffs directly behind the mobo and possibly a dead short.
 
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