Strange motherboard or cpu or power issue

[soleous75]

Hello,
I am at my wits end, I simply cannot figure this out.
I have an ASUS h270M plus motherboard with an i5 cpu.
My problem is that every now and then the computer just turns off like it simply gets unplugged. However, the motherboard lights do not go out. I can switch it on again and it will go through its thing and start windows, then 5 min later the same thing. This even happens while in bios.
Have tried everything with troubleshooting. Changed power supply, memory, taken out video card, reseated and re applied thermal paste to cpu. And tested outside of case.
I have monitored the temps on the graphics card and the cpu. When stressing the cpu it did nearly get to 80 degrees but I believe this is skylake and it should be able to go to 100 degrees. Anyway this was before I reapplied the thermal paste. tested again and it still was getting above 70 degrees.
I have turned the fans to be on full all the time and the pc is turning off with the temps at 36 to 40 degrees.
I changed in the bios to turn on again after a power loss and now after it seems to have lost power it tries to turn on again so is this an actual power loss? (the motherboard green light doesn't even flicker when this "power loss" happens as I was looking right at it when it happened.)
I always get the bios beep to say all is well, the power supply shows good 3.3, 5 and 12 volt stability. I stressed out the cpu and watched the volt levels and none went outside the 5% in fact they moved very little.
I can see no reason for this happening, and don't know what to do. It can last for days and then its unusable as it wont stay on for more then 5 mins.
Things point to the PSU which is a corsair v550, but also might be a cpu issue.
Anyway I need help and advice guys. Anything would be greatly appreciated.
Cheers
Soleous75

 

[RememberThe5th]

Didn't you try another socket to test your PSU?(I mean by powering the whole pc and see will it do again)
Have you tried one stick of ram?(switch ram if happens)
Probably bios update isn't good as you don't know when will it turn off.
Did you try with onboard GPU only?
Did you check cables inside the case?(the arrangment, soo you connected everything correctly?)
Did you try to power pc by only PSU cable to the wall, disconnect everything even monitor from wall socket, just leave PC.(I had once issue with bad grounding)
Is there moisture where you live?

I

 

[soleous75]

Hello Robert,
Short answer is yes to everything and the bios was updated to latest on install.
Left it over night, but wont even turn on now. Not by the button or by shorting the pins, there is no life except the motherboard lights are on, did this with 2 psu, no life. Took out of case with only cpu and psu on and still wont even attempt to turn on.
Tell me more about the moisture as I do not see any but it has been raining for days. Is there anything to do to keep moisture out? and could this cause these issues. Oh by the way this is the second asus h270m-plus that is acting this way first one is being RA. exact same issues. two duds? unlikely, problem with these boards? haven't heard anything. So CPU issue? or possibly moisture.

 

[RememberThe5th]

Others would blame the VS550 BUT as i have it, i've run it 2 days without ventilation in case soo 50+*C and measured the voltage with voltmeter and didn't dissapoint me.

Other factor may be which Cooler do you have, the stock or with backplate?
Did you place standoffs when putting motherboard (the little brass looking thing screw)?
Which other components do you have, Ram also can kill your PC.
If there would be moisture, imagine as you open fridge and let it and there would be like moisture on glass, as soon as you close and re-open there would be condesation aka moisture as i call.
Does your PC have exhaust fan? (yeah i said i've tested mine but i forgot to add that it had buzzing noise from capacitor soo i don't trust it much as it gets hot).

 

[soleous75]

So got the motherboard repaired by ASUS, Installed it turned on everything seems great. Looked at BIOS voltage levels, shows 5volt at 10.2 volts. Tried different psu, nope still at 10.2 volts, unplugged everything except the cpu fan, still 10.2 volts. Ring ASUS as to what the issue was and if I need to worry or just a false reading, havent got a reply yet. talked to ehere I bought it from and they said that it was probably a false reading, if everything is working, Well about 30 mins into using the computer, yet again another power loss. Black screen and pc just turns off, no shut down. Frustration doesnt even come close. No moisture in this one - Oh by the way I am using two of these motherboards and the same issue is happening on both, The other one doesnt start anymore. can the cpu be destroying the boards, could the cpu fan be shorting? I think I will send cpu in to get checked as I can think of no other possible solution. Any help again would be very grateful.

 

[RememberThe5th]

Yeah try to, cause even ram can do it...
Happened to my friend once.