Strange PC behavior, wont turn on unless it spends 5 minutes unplugged

fargerich · Feb 6, 2016

Hey Guys
this is my first thread here after being around for a while reading and troubleshooting with the great contributions!

My issue started a few weeks ago with no apparent reason (no soft nor hardware change was made to my pc) when I tried to turn on the pc and got no response at all. I'm quite tech savvy myself, (I've been putting pcs together since my first 386 with 4 megs of ram and mindblowing 80 megs of hard drive) so I started troubleshooting the system (that I've built from scratch) component by component up to the processor.
After a few hours of work the only consistent behavior is that the PC wouldn't turn on unless it spent 5 minutes unplugged.
After not getting any results with hardware testing I started working with software, I updated the BIOS (flashed the same version it had) and ran some tests to see if mem, video and processor were ok.
I'm still without an answer. The system runs smoothly and beautifully until I turn it off and try to start it up again. The only solution is to unplug the cord, count to 300 and press the button.

Here are my specs:

-CPU: Intel Core i5-6600K 3.5GHz Quad-Core Processor

-CPU Cooler: NZXT Kraken X61 106.1 CFM Liquid CPU Cooler

-Motherboard: Gigabyte GA-Z170X-Gaming 7 ATX LGA1151

-Memory: G.Skill Ripjaws Series 32GB (4 x 8GB) DDR4-2133 Memory

-Storage: 2 x Samsung 850 EVO-Series 500GB 2.5" Solid State Drive

-Video Card: 2 x Gigabyte GeForce GTX 970 4GB WINDFORCE 3X Video Card (2-Way SLI)

-Power Supply: SeaSonic Snow Silent 750W 80+ Platinum Certified Fully-Modular ATX

-Optical Drive: Pioneer BDR-209DBK Blu-Ray/DVD/CD Writer

-Operating System: Microsoft Windows 10 Pro (64-bit)

-Monitor: Asus ROG SWIFT PG278Q 144Hz 27.0"

-Sound card: Creative Soundblaster Recon 3d PCIe (beacuse Gigabyte bast***s were to damn cheap to license DDL on their integrated supposed-to-be-high-end motherboard)

Thanks very much for your comments!!!!

Ps. English is not my mother language, please excuse any grammar mistakes

profoundnoah · Feb 6, 2016

Well, we can go ahead and cross out the basics. As long as your GPU, CPU, and Memory are all working, we can leave them out of the equation. This is very hard to believe from seasonic, but it could be a 1/1million chance that you received a bad unit. I assume you've already plugged the 24 pin in again. It could be a built in surge protecting device as well. Are you hooked up to a wall, or to a surge protector/UPS?

fargerich · Feb 6, 2016

fargerich · Feb 6, 2016

profoundnoah :

Hey Noah! thanks for dropping by!

I'm usually hooked to a surge protector but for the sake of troubleshooting I've done both: surge protector (some not to cheap chicago digital power stuff) and wall outlet. Same thing
I've unplugged and re plugged every single connector from and to the MoBo and from and to the modular power supply

profoundnoah · Feb 6, 2016

Alright. Sorry for not responding promptly. Have you tried to start the system with only one card? It might be a fault in the power distribution via PCIe cords. I'm looking at your build right now, and it seems to only draw 500W, according to PCPP. It isn't a wattage issue (just to iron things out.) Keep me posted.

fargerich · Feb 6, 2016

profoundnoah :

Yup, my basic troubleshooting was stripping down the PC to its bare bones and start connecting components one by one (processor, memories 1 to 4, first VGA, second VGA, etc.). I did the same with the SATA ports and the USB polugs
The mobo has a power button with a troubleshooting led display on it and never got an alert when doing this... PC boots up beautifully until I completely power it of and wait a few minutes. Then I have to unplug the cord and wait

Bearmann · Feb 6, 2016

I'm just guessing, but I wonder if the current needs to drain out of some compacitors somewhere before it can restart. After the computer shuts down, turn off the PSU by its own switch, then hold the front computer power button in for 10 seconds. After that, flip the PSU to the on position, and then push the power button on the front of the computer.

It would be great if you could test out the system with a different PSU.

profoundnoah · Feb 6, 2016

Hmm. What store did you buy that PSU From? You may want to RMA it.

Bearmann · Feb 6, 2016

Not exactly the same issue as yours, but similar: http://www.tomshardware.com/forum/281365-28-computer-shuts-wont-turn-back-unplug

I would look for possible shorts such as loose wires and such. Try starting the computer without the monitor connected and see if it starts up (fans spinning, etc., then maybe plug the monitor back in if it starts.) Probably replace the CMOS battery too.

fargerich · Feb 6, 2016

Bearmann :

Hey Bear
The capacitors remaining charged was my first guess but there's no way to test it. I tried turning everything off and pressing the power button for 30 secs (because my cooler pump and MoBo power button remain lit for 20 secs) and nothing happened. The pc needs to be unplugged for something around 5 to 10 minutes before being able to power up again.
I thought of a short circuit to so I isolated the MoBo on every point where it touches the case with a layer of paper and some tape with no results. I'll try unplugging the monitor buy I don't know if that will get me anywhere... I think I have a spare power supply I can try and see how it goes..

fargerich · Feb 6, 2016

profoundnoah :

I want to try with a fresh PSU, but that's one of the things I'm thinking about.

Luckily I got it form amazon so return services is silk smooth

fargerich · Feb 6, 2016

Bearmann :

That's one thing I haven't done yet... I'll try fiddling around with the cables and connections to see what happens! if I don't get positive results I'll test with another PSU

Bearmann · Feb 6, 2016

I'm thinking it is the PSU, but have you tried running it with the video card removed and the monitor hooked up to the on board video?

profoundnoah · Feb 6, 2016

I don't think that would make a difference, to be honest. It's an issue with start up, not output to the display. The only time I would see that making a difference would be if the PSU's PCIe cables are somehow shorting the loop, which is very unlikely. I've already came to that conclusion that it is a bad PSU, in my previous posts.

Bearmann · Feb 6, 2016

profoundnoah :

Yes, that what is was thinking of, a possible short.

fargerich · Jun 20, 2016

Ok, its been a while but I finally managed to find a solution.
It seems I had the awful luck of picking the one-in-a-million defective Seasonic PSU.
After hours of frustrating de and re assembling my PC I tried a new PSU and voila! problem solved.
The defective unit its on its way back to Amazon and a new, Snow Silent 1050 Watts, is powering my rig.

Thanks to all of you for the time and dedication and I'm sorry about the late reply

Bearmann · Jun 21, 2016

That's for the update. It's always good to find out what the problem turned out to be. I'm glad you got it sorted!

profoundnoah · Jun 25, 2016

Glad to hear that we solved your problem.

Strange PC behavior, wont turn on unless it spends 5 minutes unplugged

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