POST stops on CPU self-test

Mar 29, 2018
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Hi guys,
yesterday I ran into a problem. I had installed a Thermaltake PCIe riser for a vertical GPU mount, and after connecting all the cables and making basic cable management, I powered it on, and while POSTing (not even got to BIOS) and all diodes were lit, it stoped o cpu light and powered itself off.
First tought was about RAM faliure, because I had some problems with it in the past, and after removing one of the 8GB sticks (2 of them in total) I got trough POST, BIOS, and went into Windows loading screen, and then it shut itself down.
Tried changing places of RAM sticks, removed the GPU (MOBO signalized that it isn't installed, but went further in POST) but after the CPU LED is lit, it immediately shuts down. Checked twice if the cables are connected to the PSU, and that there isn't any short caused by cables near the MOBO.
Tried to run without any HDDs/SSDs connected, it by first got me to BIOS with an info that "the boot device isn't supported" and than the shutdown.

[Maybe can be useful: MOBO software a few months ago started showing warnings (in OS) that the 5v, 3v and the others had too low voltage]

PC specs:
-MOBO: ASUS TUF Sabertooth 990FX R2.0
-CPU: FX-8350
-CPU cooler: Corsair H115i
-GPU: Strix GTX 1060
-Storage: 120GB Intel SSD (boot drive); 1TB Seagate HDD; 2x Seagate Firecuda 2TB (not in raid)
-RAM: HyperX Fury Black 1866MHz CL10 2x8GB
-PSU: bequiet! DPP11 850W Platinum
-OS: Win 8.1 Pro 64-bit
 
Mar 29, 2018
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I've updated it some time ago, when the last update from Asus came. It was like mid 2016.
Link to last BIOS update: https://www.asus.com/Motherboards/SABERTOOTH_990FX_R20/HelpDesk_BIOS/


 

Have you tried to run with out your 3 mechanical hard drives? Could one be failing?
 
Mar 29, 2018
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Tried with the HDDs, but didn't check the SSD. Would a drive jam the startup in such a way, that it would stop the pc from properly posting?
(Gonna check them properly with MHDD when i will be back from work)
 

I can't say for sure if it would prevent the computer from starting up, but a failing hard drive can cause a PC to freeze and crash.
 
Mar 29, 2018
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Ok, so I checked again disks, no bad sectors or sth. Used the bios flashback to update it, no changes. But when I tried to run the system without some power connectors, with cpu unplugged, the mobo didn't even try to go into post, it just gave power to the fans and rgb on gpu, and the cpu led was lit (no processor detected).
I will now check voltages outcoming from the psu, to check if it didn't fry the cpu or the mobo doesn't accept too low/high voltages.
 
Mar 29, 2018
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Tried with GPU plugged directly to MOBO - no changes.
Checked voltages outcoming from the PSU - all12v, 5v, and 3v rails give proper power output.

I think that I might fry the CPU somehow...
 

When you installed the Thermaltake PCIe riser you may have knocked the CPU cooler loose. Try removing and reinstalling the CPU and CPU cooler, check for any bent pins on the CPU just to be sure.
 
Mar 29, 2018
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Checked that, took off the corsair block/pump unit, took out the cpu, checked for any bent pins, tried once again reinstaling cpu, than the RAM - still no progress.
 

Have you checked for any dirt, lint or pet hairs in the PCIe and RAM slots?
 
Mar 29, 2018
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Yep, even looked for thermal paste that could get around the cpu or in the socket - everything is clear.