[SOLVED] PC suddenly stopped booting, tried everything, can't understand the problem ?

[moodyzxy]

So my pc started to turn off unexpectedly yesterday. Tried to look for a fault but couldn't find any. It was working fine after shutting down twice.
Finally i wasn't able to turn it on, it would boot and shutdown again. I took apart everything, cleaned the motherboard, replaced the thermalpaste etc.
Did the paperclip test on the psu, it was working fine . I tried booting with only the processor on the motherboard and even without it, but the psu will only tick once and then nothing.
What I've noticed later that the system would run after a few hours and then turn off after a few seconds. Didn't got a chance to run it with the ram and the gpu so i can see if it posts.
Is it a motherboard problem ? I've been scratching my head all day now.

My system specs:
i5-9400f
Asrock z370pro4
Corsair 32 gb ram
Corsair hx750i psu

 

[Lutfij]

Happy New Year!

The paperclip test on the PSU is moot, it doesn't tell you much power the PSU in question(or under clipping) is capable of outputting effectively. How old is the PSU in your build? You might want to source(borrow) a PSU from a friend or neighbor who owns a reliably built unit to rule your PSU out as the culprit. I also noticed, you forgot to mention the make and model of your discrete GPU. You won't get display output when connected to the motherboard's display output ports since the processor you own(the F suffix) lacks an iGPU, hence the F at the end of the 4 digit number for the i5.

 

[Aeacus]

Did the paperclip test on the psu, it was working fine .

Wrong way to test PSU.

Paperclip test of PSU is like turning on the car engine, without doing the test drive.
All this does, is like you turning on the car engine and when engine starts, you instantly assume that the car drives just fine, without ever doing the test drive.
So, no. Just turning on the PSU, without putting any load to it, doesn't mean PSU works fine.

Didn't got a chance to run it with the ram and the gpu so i can see if it posts.

Without RAM installed, system will not POST.

Btw, what GPU you have?

Corsair hx750i psu

While good quality PSU, there are lemons, even among the best.

Here, i'd look towards PSU replacement, since random shut downs are mostly either caused by PSU or high thermals.

Once the new, good quality PSU is in place and you still get issues getting your PC to work, then look towards MoBo replacement. Since it is possible that you MoBo died. Though, MoBos usually die when PSU starts acting up.

 

[moodyzxy]

Thank you for helping, my gpu is msi 1660ti, and i haven't plugged it in since the problem.
So i think I'll try and borrow a psu from a friend.

 

[Aeacus]

and i haven't plugged it in since the problem.

Like Lutfij said, since your CPU is F-series, it won't show any image on monitor without dedicated GPU in the system. While system can POST (with CPU-MoBo-RAM and PSU), you can't tell much diff if it does, when you have 0 signal on monitor.

 

[moodyzxy]

So i bought a new psu and tried it, everything works fine now.
Thank you for the suggestion and help!
Best wishes!