Challenging issue: PC switches on for a split second then powers off.

[IntelVEVO]

I have a PERSISTENT issue with my computer that I built which started happening 2 weeks ago without any notice. When I shut down the computer and start it back up it flickers on for a split second and switches off again. I have gone through multiple trouble shooting procedueres including removing the board from the case, start without RAM starting without GPU, and a complete reassembly and remounting of the motherboard and removal of CPU from its socket. The PSU seems to pass the paperclip test and operates normally. But when I plug the 8 pin CPU and 24 pin ATX leads... the issue occurs no matter what. When I remove the 8 pin CPU the system light up and fans spin constantly but does not boot.

Now here is the REAL strange part. I manage to get it to boot eventually operate normally. But I have no idea how sometimes the system just fixes itself and works completely fine. this usually happens when I spam the power button for a while and plug in extra usb/sata peripherals but this fix doesn't always work. This issue only happens when I shut down the system which is why I now keep it running constantly.


MSI z170A pro gaming Carbon
2 x 8GB Crucial Ballistix Sport DDR4 2400mhz
Intel Core i7 6700k
Palit Gamerock GTX 1080
Corsair CX600 power supply
Bitfenix aroura case (built in standoffs)
Coolermaster Sedion 240V waterblock

 

[Dunlop0078]

Well my first thought is a short somewhere like an unused standoff touching the bare pcb on the bottom of the mobo. Usually when you have a short the pc will power on for a second then the short circuit protection in the psu will activate and shut it off. However that does not explain why it works sometimes. I'm not really sure, personally I would pull the motherboard out make sure there are no unused standoffs, I see that you said they are built in but if that case supports micro atx boards as well it should have some removable standoffs. Also check for screws that may have gotten under the board and other debris. Also check all your power cables for a secure fit.

If that doesn't work I would remove everything thats not vital and try to boot. All the fans besides the cpu, take out the gpu, leave one stick of ram, only your boot drive, no USB devices, and try to boot. If you still have no luck I might try a different outlet on a different circuit in your house.

 

[RaDiKaL_]

I'd say there are 3 possibilities:

1.- Your power options in BIOS like Intel Speed step, C6 state and such that are usually modified for OCing are not at their default values, when you leave some enabled instead of disabling them all for OC it can cause your problem.

2.- A capacitor or other similar component in your mobo is failing, taking it several boot attempts to properly charge to maintain the system running.

3.- A capacitor or other similar component in your PSU is failing, having the same issue as explained above.


Verify your BIOS options are properly set, keep in mind that Corsair CX series are built with low quality components, a quick google search will show you how many ppl has got issues with this PSU after just a few months of use, but lets try the BIOS options first before jumping into any conclusion.

 

[IntelVEVO]

Well my first thought is a short somewhere like an unused standoff touching the bare pcb on the bottom of the mobo. Usually when you have a short the pc will power on for a second then the short circuit protection in the psu will activate and shut it off. However that does not explain why it works sometimes. I'm not really sure, personally I would pull the motherboard out make sure there are no unused standoffs, I see that you said they are built in but if that case supports micro atx boards as well it should have some removable standoffs. Also check for screws that may have gotten under the board and other debris. Also check all your power cables for a secure fit.

If that doesn't work I would remove everything thats not vital and try to boot. All the fans besides the cpu, take out the gpu, leave one stick of ram, only your boot drive, no USB devices, and try to boot. If you still have no luck I might try a different outlet on a different circuit in your house.

I have triple checked the standoffs and tried the computer at different locations as well as starting it without ram with 1 stick of ram without gpu in but I haven't found
A condition that will enable the system to boot successfully 100% of the time. As reluctant as I am I guess I will have to consider returning the mobo

 

[IntelVEVO]

Found a solution. Unplugged the 4 pin part from the 24pin atx and the system boots flawlessly. Maybe the 24 pin was pushing too much current to the motherboard causing it to shut down. Ah well works fine now and nothing was faulty which is a relief.

 

[RaDiKaL_]

That's not really a solution, those extra 4pin in the 24pin ATX are the ones that give power to your PCI-E for your video card. Seems like your PSU is being unable to properly power your GPU.

 

[IntelVEVO]

That's not really a solution, those extra 4pin in the 24pin ATX are the ones that give power to your PCI-E for your video card. Seems like your PSU is being unable to properly power your GPU.

My GTX 1080 seems to work fine though even with a overclock. Boosts to 2050MHz and games perfectly. Its power delivery is quite beefy as has one 6 pin and one 8 pin connector so maybe it doesnt need extra power from the PCIE after all.

 

[RaDiKaL_]

While it might be getting enough power via its extra PCI-E power connectors, the 24pin ATX shouldn't cause any issue at all, better change that PSU once your budget allows it, don't risk your overall investment.

 

[IntelVEVO]

Damn. Ran into this issue again. Changing PSU didn't work either. Guess I will have to RMA the motherboard. Probably a manufacturing defect since my system is only a month old..

 

[RaDiKaL_]

If you haven't sent it yet, try breadboarding your system, a short could be causing your problem, since the GTX 1080 is a beefy card sometimes it can bend your mobo just enough to cause a short, give it a try while dismounting your mobo before sending it to RMA.

 

[IntelVEVO]

If you haven't sent it yet, try breadboarding your system, a short could be causing your problem, since the GTX 1080 is a beefy card sometimes it can bend your mobo just enough to cause a short, give it a try while dismounting your mobo before sending it to RMA.

Yeah I bread boarded with nothing but CPU and switched between 2 PSU using a screwdriver to short the 2 power pins and it wouldn't even beep to indicate ram was missing. The MSI EZ Debug LED for CPU would flicker breifly. But when I gave up and reassembled it in the case it bloody turned on! I am currently using it to type this post and haven't turned it off since I got it working. Its bloody strange.