After Shutdown, LED and Fans stays on, holding power button does nothing

[crystalpaladin]

Components(every component listed is just 5~6 months old)
Motherboard: Gigabyte Aorus Z370 Ultra gaming 2.0(rev1.0)
Processor: 8th gen Core i7-8700(non-k version)
PSU: Corsair CX650M
Ram: corsair vengeance 8GB DDR4 2400 Mhz C16 - single stick
Storage: Samsung 960 Evo 250GB NVMe M.2
Case: Corsair Carbide Spec3
GPU: Onboard intel graphics only
Power: Clean power - APC UPS 1100VA
Two system case fans and I don't OC nor do I run multiple applications at the same time... at most, I'd run Guildwars2 MMORPG but I hardly suspect that's an issue

Scenario1
When I use my PC for less than ~ 30 mins: Everything is fine... turns on properly, shutsdown properly(with windows start->poweroff and the case powerbutton), restarts properly, i can play MMORPG games properly... no lags and no issues everything is perfect

Scenario2
If I use the PC for more than ~ 30 minswithout shutting it down, there are no issues with the operation and I can play games, Browse the internet, watch movies, listen music... no issues, no BSOD, no freeze, no hungups, but when I decide to turn off my PC, the OS shuts down and monitor switches off but the fans and LEDS won't go off. waited for 5 whole minutes... it won't power down... pressing the case power button does nothing... press and hold the power button for 10 seconds does nothing either... Hard power off by pulling the plug is the only way... If I try to power on the PC, the fans and LEDs will start and stop like some kinda morse code signal but won't bootup(no beep)... keeping the PC disconnected from power source... after that, my PC won't POST properly and boot until the next day... the next day this repeats... at this point i'm scared to poweron my PC suspecting some component might go bad beyond repair


Last event that I did before encountering these issues
Updating the Intel graphics drivers(with game booster presets for fortnite, wow,...) with the intel driver assistant software(approximately sep3 2018)


Troubleshooting Performed
1) Updated motherboard chipset drivers followed by intel vga drivers from gigabyte website w..r.t the motherboard
2) Removed and reseated all components connected to Mobo
3) Checked the startup apps(if any) which might be controlling mobo - found nothing there
4) Reset Bios settings to optimized defaults
5) Checked the Ram Frequency in bios settings - no issues there
6) CMOS battery seems fine - date time settings - system clock shows the correct time and bios settings are saved and retained after poweroff - poweron
7) RMA'd the motherboard to Gigabyte(still under warranty) and they reported there are no issues found and the mobo is perfectly functional (though I suspect that... coz the issue is replicated only after ~30mins of usage... I mentioned that explicitly while RMA'ing it)
8) Suspected PSU might allow only power on and not power off when using the case power button - but power on and power off works perfectly when using the case power button when PC usage is less than ~30 mins
9) WakeonLAN, WakeonMouse, WakeonKeyboard is not set


Steps not yet done
Removing the CMOS battery - I'll try this and reset CMOS but I hardly doubt this'd fix the issue
Reflashing the BIOS - since PC operation is perfect within 30 mins, i doubt this'll help. MOBO has the latest BIOS F4... but I'll try this if I'm desperate
Reinstalling Win10 - case powerbutton overrides the OS and the fact that it doesn't POST after hard shutdown, i hardly doubt that OS could be a culprit
MemTest for RAM - heard it'd take more than 6 hrs... and the fact that my PC works perfectly before shutting it down, decided to reduce this step's priority
Haven't checked if the PSU fan is functional


Is there some kind of component that has a possibility of misbehaving after some time of usage(may be due to heat)
Some guy explained in a thread that there's a chip in mobo that controlls the case powerbutton to PSU connection and that could be an issue... but the power button functions properly if usage is less than ~30 mins

Is this due to static electricity? if it is, why not show those symptoms when using it less than ~30 mins

Is it coz of keyboard and mouse shorting something out in the board? if so, how do I confirm?

All these years, I've never encountered or heard of this issue... Plzzzz someone, lead me in the right path... I don't have a spare PSU to test with... If I have to replicate the issue, I need to use the PC for ~30 mins else I can't convince Gigabyte service guys and they'll conclude there's nothing wrong with the board and they'll simply return it to me

Hope this doesn't drag onnn until the warranty expires

 

[terry4536]

If no improvement was made, returning the power supply (as suggested) is a good idea.

sorry for the delayed post... Only y'day did I get my replacement PSU from corsair(they delayed it for almost a month)... got a new CX650M and still the same issue..

My PC works and if I try to restart the PC, OS shuts down properly and then it just loops restarting without passing POST... the fans spin for 5 seconds and then powers of for a second and then spin for 5 seconds and repeats it forever... nothing happens if i press the power button... only option is to use the hard poweroff by switching off the UPS or using the PSU switch at the back of the case

Is it possible that my motherboard gone bad?
Is it possible that processor can work for half an hour and then malfunction after restart?
Will faulty RAM exhibit this kind of behavior?

Will a drained CMOS battery cause this?(coz previously i used to turnoff the plug after shutdown and the CMOS battery might've drained)

When you power up the system now, does it still go into a restart loop? If it is try clearing the CMOS again. Hopefully that will get you past POST. You have had a CPU error before, and a CPU problem can cause a restart lop like that.

It has been a while, did you remove the CPU check for bent pins or thermal paste in the pins?

I'll check the CPU pins today...
But y'day my PC didn't malfunction during one and half hours of operation when I ran MemtestX86 and only when I restart it, did my PC goes into the restart loop... as far as i understand, if one of the cpu pins are bent, it won't even POST, much less operate for an hour without any issue

the problem is I couldn't reliably reproduce the issue unless I keep my PC switched on for more than ~30 mins... this gets me in awkward situation when I would get my board,cpu,ram to the service centers, It'd run just fine and it wont go into restart loop even if i restart it multiple times... the next time I'll make sure it runs for atleast 30mins in service centre before restarting it...

Yes, that is the problem with intermittent problems. It may take 5 minutes to fail, or it may take a day or two.

 

[crystalpaladin]

Today I went to RMA my motherboard, when the tech service guy checked it with their PSU and their display, My board didn't pass the POST process and entered a loop... Then he took my board and went inside a closed room and returned suddenly telling me that the board doesn't have any issues and its working just fine and he checked it with a different PSU... I asked him why it didn't POST when he showed it to me during the first time check and he made a lame excuse that the PSU that he tested the board with the first time isn't compatible with the board. I asked him the PSU specs and he told me its a 450W Gigabyte PSU... While testing my mobo, it was at its utmost minimal load(motherboard, i7 8700 non-k processor, 8gb ram 1 stick, 1 nvme m.2 and no other components attached no Graphics card no HDD no nothing extra)... This minimal setup can't be drawing more power and definitely not above 450W... then why did my brand new RMA'd CX650M corsair PSU couldn't get my MOBO past the POST process?
The last time I went to that service centre, I checked my motherboard in their same PSU(450W) and I couldn't recreate the issue and it passed POST and Boot into windows properly. why couldn't it be compatible with the mobo now and it worked last time(during previous visit)?

Sorry for the ranting... I just don't know what else to do right now...

My RAM passed the complete MEMx86 test 2 times without any failure
If my nvme m.2 is the issue, mobo should atleast show me the BIOS screen but it didn't even pass the POST process
Would my processor cause all these ruckus? would a processor cause a system to fail POST process after a restart or a shutdown?

If my RAM failed the memtestx86, I could RMA it... but without any issues I can't raise an RMA...

I'm totally stuck here... my head is between a rock and a hard place

 

[crystalpaladin]

Yes, that is the problem with intermittent problems. It may take 5 minutes to fail, or it may take a day or two.

would a faulty processor cause this issue?... Is it possible? AFAIK, faulty processor won't even allow to boot not even once... or am i mistaken? idk

 

[terry4536]

Did you check the CPU pins?

Although it depends upon the degree a CPU is damaged, most often a faulty CPU would fail to boot. I don't think a faulty CPU would cause the problems that you described.


Do yo have a case speaker? I would get one. The beep codes can provide information on the problem.
Here is an example below.

http://www.newegg.com/Product/Product.aspx?Item=N82E16812201032&cm_re=case_speaker-_-12-201-032-_-Product

Once you have the case speaker installed, test it by rebooting. If the system boots up, you should have a single long beep at startup. Another test is to remove the RAM, and then start up the system. You should have repeated beeps when you turn on the system. The case speaker isn't keyed, so it is possible that the case speaker needs to be rotated 180 degrees.

 

[crystalpaladin]

Did you check the CPU pins?

Although it depends upon the degree a CPU is damaged, most often a faulty CPU would fail to boot. I don't think a faulty CPU would cause the problems that you described.


Do yo have a case speaker? I would get one. The beep codes can provide information on the problem.
Here is an example below.

http://www.newegg.com/Product/Product.aspx?Item=N82E16812201032&cm_re=case_speaker-_-12-201-032-_-Product

Once you have the case speaker installed, test it by rebooting. If the system boots up, you should have a single long beep at startup. Another test is to remove the RAM, and then start up the system. You should have repeated beeps when you turn on the system. The case speaker isn't keyed, so it is possible that the case speaker needs to be rotated 180 degrees.

My CPU doesn't have pins... It has gold contact points... I did a thorough observation on the CPU contact points and they all seem fine... except a teensy tiny dot of oxide layer formed on one gold contact point(i used a cotton swab and now the tiny dot is hardly visible) but I really doubt if that's what causing the issue

Now I've submitted my motherboard for testing with gigabyte tech service personnel... once I get it back, i'll use the mobo speaker if I encounter the same issue once again

 

[terry4536]

The pins are in the Intel motherboard socket.

AMD has the pins on the CPU.

 

[smorizio]

if you can rma the mb theough the vendor tell them the mb has bad vrm or a bad trace. it sounds like there a broken trace that seals when the mb or part gets warm.

 

[crystalpaladin]

if you can rma the mb theough the vendor tell them the mb has bad vrm or a bad trace. it sounds like there a broken trace that seals when the mb or part gets warm.

I went to the Gigabyte Authorized service center... Initially they convinced me by booting up and restarting and shutting down the OS and no issues popped up... I insisted them to let it stay on and told them to play a video file on repeat for 20 mins... then we checked it by restarting it... and the issue popped up... all the while its been connected to their own CPU, PSU, HDD, RAM... Then and only then they accepted that the issue is with the motherboard... I fear I have to spend my entire life trying to prove these kinda stuff... why can't they have a complete motherboard testing procedure??? else they'd have convinced me that nothing's wrong with the mobo and I would've threw my PC out the window :/

Thanks guys for the support... and quick responses... pardon my delayed responses