Question My pc shuts down randomly but the case doesnt lose electricity

moking01

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My PC shuts down completely random during windows operation at no consistent pattern. The monitor just turns blue and after a while it goes off as if i did shut down the PC.
On the other hand the case LEDs, RAM, AIO...everything still operates. But i dont hear any sound coming off the speakers.

also it wont turn back on immediately. i have to disconnect the power cord and the PSU switch for couple of minutes before i can get it to turn on again

Ryzen 1600
Asus b350 rog strix
gtx 1060 3gb
seasonic s12iii 550w
16gb corsair vengeance
fresh win10 installed
Im not running any sort of overclocking


things i tried

- tried clearing cmos

- tried to stress test my gpu under furmark for 30 mins and temps maxed at 79c

- ran a 3.5 hours memtest for both ram and cpu and came out with 0 errors

- installed fresh windows

- ran a hd essentials check on my hdd/ssd and found that my kingstone a400 was dying (15% health) so i took it off and installed windows on an old hdd
 
Last edited:

R_1

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suspect number 1: Seasonic s12iii 550w
the 550W 500W 450W units ARE NOT seasonic made units simply sold by seasonic. the 520W and 620W units are Seasonic made.
do you have access to another system you could swap the PSU and see with each system testing the other?

My canned random reboot Rant
Random reboots are usually caused by the PSU, the RAM or software AND in that order of likely-hood.
PSU - If you can borrow/swap a PSU for testing. sibling/friend you can swap out the PSU and each system will be testing the other.
RAM - run the system with one stick of RAM see if stability returns if not Test all the RAM with memtest 86 for five passes or overnight. if you get no 0 errors after more than five passes the ram is good. with the random reboots I would suggest running this test after the PSU swap or after the PSU has been cleared.
Software - Drivers or other issues can cause reboots. Boot to a linux distro on a USB drive. mint linux will boot to memtest86. you can run the OS from the USB and await reboot.
end canned rant

3.5 hours is a cursory memory test at best. did the memtest even complete 1 pass of the cells? 5 passes no errors usually means ok, some suggest 10 passes but that could take days.

"i have to disconnect the power cord and the PSU switch for couple of minutes before i can get it to turn on again "
in my experience this is indicative of a failed PSU.
 

moking01

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Sep 27, 2014
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suspect number 1: Seasonic s12iii 550w
the 550W 500W 450W units ARE NOT seasonic made units simply sold by seasonic. the 520W and 620W units are Seasonic made.
do you have access to another system you could swap the PSU and see with each system testing the other?

My canned random reboot Rant
Random reboots are usually caused by the PSU, the RAM or software AND in that order of likely-hood.
PSU - If you can borrow/swap a PSU for testing. sibling/friend you can swap out the PSU and each system will be testing the other.
RAM - run the system with one stick of RAM see if stability returns if not Test all the RAM with memtest 86 for five passes or overnight. if you get no 0 errors after more than five passes the ram is good. with the random reboots I would suggest running this test after the PSU swap or after the PSU has been cleared.
Software - Drivers or other issues can cause reboots. Boot to a linux distro on a USB drive. mint linux will boot to memtest86. you can run the OS from the USB and await reboot.
end canned rant

3.5 hours is a cursory memory test at best. did the memtest even complete 1 pass of the cells? 5 passes no errors usually means ok, some suggest 10 passes but that could take days.

"i have to disconnect the power cord and the PSU switch for couple of minutes before i can get it to turn on again "
in my experience this is indicative of a failed PSU.
Thanks a lot for the info. I checked the PSU box again and its a 520w model not a 550w. Not excluding it from the possibilities, just correcting myself.

Its so hard for me to get a spare PSU right now. Specially that the shutdowns happens completely random. Might take couple of minutes and might take hours.

The RAM test passed 4 phases not 5. Would it make a difference ?

I suspected bad drivers too so i installed a fresh win10 and it happened again.

For now i plugged the power cord into a different wall socket to see if that might cause an issue. Is there a software or tool to test the PSU without swapping it ?
 

moking01

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4 passes should be fine to rule out the RAM.

the only real test of a PSU is a PSU tester (hardware not software) and good old fashioned trial and error.
example only not an endorsement shop around
https://www.newegg.com/rexus-pst-2/p/N82E16899705002?Description=power supply tester&cm_re=power_supply_tester--99-705-002--Product

if it is the PSU it has a 5 year warranty
I have not yet tested the PSU as i was in a vacay, but when i removed the dust filter beneath the PSU shroud...i noticed that the PSU fan is spinning relatively slow. Not slow in the sense that i can see its blades....but slower than say case fans or AIO fans.
Its the first time to actually observe a PSU fan so i dont know if thats the normal spinning speed or its slow in my case. Might be a PSU overheating at some points that it shuts off ?
Is there a way to set fan curve for a PSU ?
 

moking01

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Went out today and grabbed an Aorus P750W +80 Gold. Found the Focus plus at the same price but saw some bad stuff about it on LTT forums so i just avoided it and went for the Aorus unit.