2 dead motherboards in a month... PSU, case, or something else?

Associate
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My PC was running fine for 23 months until last month. For a couple of weeks it had felt like I had to press the power button harder than you’d expect before it would start, then it just refused to boot with no signs of life (including shorting the power switch pins)

Replaced the motherboard (Gigabyte Aorus Ultra Gaming Z370 replaced by Gigabyte Aorus Z390 Elite) and it’s been fine until a day or two ago when it started doing the same thing, and this morning it won’t start. The symptoms are identical - literally nothing happens when I press the power button, and if I disconnect the PSU, wait 5 minutes and reconnect it, the Motherboard LEDs light up for a split second before going dark again. That’s the same thing I saw last time, so it looks like an identical failure

Presumably the new motherboard is dead too, but that seems like too much of a coincidence and I’m now wondering if my PSU (EVGA 650 GQ) is faulty, or my case (NZXT H700i)button is doing something weird and causing the motherboard to develop problems. Presumably something else is causing the issue, but I can’t work out what... or whether it’s possible my CPU/RAM/GPU/SSDs or even a fan or cooler is causing the issue

How do I diagnose the root cause? Help! I don’t have the time, stress levels, or cash to tear my PC down every few weeks to return dead components :(

Full specs

  • Gigabyte Aorus Z390 Elite
  • Intel i7 8700K (preciously 4.9GHz, now stock)
  • 16 GB Corsair Vengeance DDR4 3200MHz
  • Gigabyte GTX 1080
  • NZXT H700i
  • Corsair H110i
  • Samsung 960 Evo M2 SSD
  • Samsung 860 Evo/Crucial M500(?) SATA SSDs
  • The fans and LED strips that came with the case and cooler, and an NZXT Hue original RGB strip
  • EVGA 650 GQ PSU
 
Last edited:
Soldato
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Well it sounds like a faulty button so I'd start by disconnecting the button from the motherboard and shorting the pins on the board manually with a screwdriver or something similar :)

believe OP has performed this.

first stag is to rebuild outside of the case without GPU and Storage with one stick of ram and CMOS cleared .

Mobo would have a fault LED at the bottom right hand side indicating if its CPU/RAM/GPU or mobo if the system would power on for a few seconds (though this could be the Pro model and above )

about quality of your PSU

https://linustechtips.com/main/topic/1116640-psu-tier-list-40/
 
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OP
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I haven’t actually shorted the switch header yet on this motherboard, but I’m 99% sure it won’t work as the symptoms look identical to my issue a month ago. I will try it (along with CMOS battery) but I’m fairly confident it won’t help

I thought the same thing about the case switch, but once I added a new motherboard it’s been perfect for a month: so it feels to me like the switch issue is a symptom of the PSU/Motherboard

What I really need to know is, could it possibly be anything else? Is it possible another component is causing the issue and is there any way to narrow it down? I can’t just replace my motherboard and a random component every month until I find the cause
 
Soldato
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For sanity's sake just build it outside of the case as Orbi has suggested. You could have a short, it could be a faulty component, either way you might end up stripping it down again.

If you can't be bothered to sort it out, or just don't have the tools or spares, I'm always happy to help a fellow OCUK'er if you want to fetch it over. :)
 
Soldato
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Could try testing cold booting with minimal parts, meaning using integrated GPU instead of separate and having no drives connected.
Though working for some time hints toward motherboard or PSU.
 
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OP
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Yeah I’ll go through a full strip-down and test regime later when I have time just in case, but I’m 99% sure it’s the same as a month ago - it’s showing literally identical symptoms and that’s a hell of a coincidence otherwise

So I’m 99% sure the motherboard is dead, but I don’t know what component is making it blow up

I’m mostly just trying to work out what the likelihood is that the PSU is the problem, or whether there’s any way to try to identify the cause
 
Soldato
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I take it you have examined all your PSU cables and plugs for signs of damage, melting etc ? Think about getting something like this cheap as chips to test outside the case if you cant find anything visual.

https://www.overclockers.co.uk/b-gr...socket-1151-ddr4-atx-mb-6bh-as-bg-95g-as.html

Also google PSU tester and pick one up for less than a tenner. I've had mine years and I mean years, used it only about 5-6 times and everytime its been worth gold as it has helped me out.
 
Soldato
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Have you used a PKE meter to check for unusual paranormal activity? Is your house on a lay line intersection or situated on an ancient Indian burial ground?
 
Associate
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I had a similar thing happen to my z87 system ... I tried many things and thought it was my Gigabyte motherboard (dual bios) or PSU, it ended with a corrupt bios on both dual bios's that made the board refuse to boot at all.

It wasn't until I sold the DDR3 RAM off and buyer complained that one of the RAM sticks didn't work that it may have been that.

So try to boot with only 1 RAM stick in the system.
 
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OP
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Update: as suspected, the system won't boot in any configuration I'm able to test (listed below, let me know if I've missed any potential combination given that I only have one LGA1151 motherboard/CPU, and two sticks of DDR4)

- Removed from case
- Removed drives
- Removed GTX 1080 and used onboard GPU
- Tested with two different monitors (and two different cables, also tested with no monitor)
- Switched PSU for a known-good working PSU
- All USB/front panel etc headers removed
- All ethernet etc peripherals removed (also tested with two different keyboard+mouse combinations)
- All non-CPU-header fans removed (also tested with two different fans, and with no fans at all
- Removed both sticks of RAM and then tested with each stick in all 4 slots by itself
- Removed and re-seated CPU and cooler

The only things I haven't been able to do are test completely new RAM, CPU, or motherboard (since I don't have any others), but the result has always been the same... not so much as a flicker from the fans/lights when pressing/shorting the power

The GPU, PSU, and drives all seem to work fine in another system.

I've ordered the motherboard above because I'm sick of not having a spare 1151 motherboard anyway so for £30, **** it... I also have a PSU on the way from OcUK (Corsair RM 650i), and a UPS ready to buy in my Amazon basket

I'll test with the new motherboard on Monday, then RMA it if it is indeed broken: I'll also be RMA'ing the PSU and letting them test it... either way, it isn't going in my system again.

The current plan is to build the system in my spare case, and run my fiancee's PC in my case (old 1150/DDR3 system, if it dies who cares) so we can see if the case power switch is a problem: hopefully between that and a new PSU/UPS, I won't have a recurrance of the problem.

I love PC building... but not when it goes wrong :(
 
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OP
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Plot twist: It's the case and I was shorting the wrong pins on the motherboard. Either that or I had the right pins and the power switch issue had messed up the CMOS which resolved after I left the battery out overnight.

Either way, when using the power switch from another case and connecting the correct header, the motherboard seems to fire up just fine. Luckily the case has about 3 weeks of warranty left, so this was a good time to realise the culprit!

I'm slightly tempted to keep the RM 650i though when it gets here ... and the UPS is staying regardless, I feel like I want that peace of mind now
 
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