Random shut down with blinking caps lock

[yash-j]

My Product Number is T9Y67AV. The System Board ID is 820C. BIOS Version is F.52. BIOS Vendor is Insyde. The problem I have been facing is random shut down.

The caps lock blink pattern after the shut down is 5 equally spaced blinks followed by a brief pause followed by 3 quick blinks followed by another brief pause and then the cycle repeats. I have to shut down the laptop by pressing the power button for about 5-10 seconds.

Please note that the problem is not with booting up. I can boot up in Windows 10. Its just that after opening a couple of apps, the laptop shuts down randomly. The problem doesn't seem to be with battery as this happens with both plugged in and on battery. The fan DOES NOT make any noise before this happens. In fact, it does not make ANY sound at all. However, the problem doesn't seem to be the mechanical failure of the fan because when I updated my BIOS trying to solve this problem, the fan went on full speed during the update (you could judge by the sound it created, never happens in Windows). Another observation - the issue never seems to take place when I am in BIOS settings. And the issue persists when I try to boot up in Ubuntu.

The thing that has been bugging me is when I ran the extensive test on HP Hardware Diagnostics UEFI (the one that runs for more than 2 hours), it passed. All checks were passed. 

Summing up,

I CAN boot up.

The shutdown happens randomly and caps lock does a 5 blink - 3 quick blink pattern.

The random shutdown happens both in Windows and Ubuntu.

Happens during both plugged in and not plugged in.

Never happens in BIOS setting.

All checks of HP Hardware Diagnostics UEFI passed. 

I am really tired of the issue. Can't do any work on my laptop. Please help and please consider all of the mentioned information.

[Lil_Boy_Blue]

Hi
Depending on the age of the PC and the BIOS vendor...

https://support.hp.com/us-en/document/bph07107

It is a Main Board issue.

Common to both OS's so RAM or HDD are the less expensive options.

Ubuntu will run as a LIVE distro so that could eliminate the HDD if you tried it.

Video also common and of course CPU etc.

BIOS update is a No-Cost/Lo-Cost option also.

[yash-j]

Thank you for your reply. The random shut down happens when running the live version of Ubuntu (the 'Try Ubuntu without installing' option). The LED documentation is helpful but what I can't wrap my head around is, if there would have been a main-board issue, how did my laptop boot-up in the first place?

The laptop was bought in January 2017. And the BIOS vendor is Insyde.

[Lil_Boy_Blue]

Hi

Because the fault is intermittent, time or temperature sensitive.

Which is why things pass the "POST" and fail a few minutes later.

So ubuntu use rules out the HDD, probably.

So CPU or RAM would be my next suspects.

But I am as mystified as you are.