Newly built computer turns on for 1 second then turns off

[thebigjt]

Hi Everyone

I'm having a slight problem with a newly built PC which I've never come across before but it might be a feature of the power supply. I haven't overclocked anything or attempted to.

I switch off at the wall overnight. When I power on in the morning, the fans spin and machine switches off after 1 second and then boots as normal about 2 seconds later and all is OK. I shut the machine down leaving it switched ON at the wall and when I get home from work the machine boots with no problems.

There's no loose cables or connections, everything is seated OK. The problem only happens when the power is switched off at the wall, even for about an hour - tested last night.

My old PSU is a 10 year old Nesteq 600w and I don't think it's powerful enough for the new kit - don’t want to blow anything up.

Apart from this, the machine works all day without crashing even when gaming. Is this a feature or is something faulty? And will it damage anything?

Machine specs

ASUS Prime Z370-A
64gb Corsair Vengance LPX ram
8th gen Intel i7 8700 3.2ghz (not the K version)
Nofan CR-80EH CPU cooler
EVGA GTX 1080
Creative X AE-5 soundcard
2x 1tb M.2 drives
FSP Hydro G 750w PSU
Jonsbo UMX4 case with side windows
Win 10 Home 64bit

Regards
Ian

 

[sonofpern]

I'm not a pro, but I'd start with checking the PSU any way you can. Just to be clear, it starts up and then shuts off immediately, but then starts back up on it's own right away? And it only does this if the PSU is disconnected from power as well? Or are you pushing the power button after it shuts itself off? If I remember right, older PSUs have a different current distribution to the rails that may not provide certain components with enough power right away. Maybe the PSU is taking too long to get to full power, but the behavior is still odd to me.

 

[thebigjt]

Hiya, Thanks for the quick reply.

it starts up and then shuts off immediately, but then starts back up on it's own right away?

Yes. About 2 second delay.

Switch on at wall, push power switch, turns off immediately, 2 second delay, switches on by itself and all is OK, no need to press the power button again.

Only happens after it's been switched off at the wall. The PSU is a new FSP 750w, bought about a month ago.

Regards
Ian

 

[sonofpern]

have you tried turning the power supply on for a minute before booting the computer? That might help narrow it down to the PSU itself, could even be a loose connection given the age of the PSU. Do you have any access to another PSU to hook up and test? It could easily turn into a bigger problem, even damage, depending on where the fault is.

 

[sonofpern]

or do you have access to a multitester to test your PSU?

 

[thebigjt]

I think I've confused the issue. The PSU is a brand new FSP Hydro G 750w bought about 2 months ago. Anyway, I swapped out the power supply with my OLD Nesteq and the problem still happened so not a power supply problem.

I've also swapped the motherboard battery - still happened. I booted without the graphics card, the soundcard and one of the M.2 drives and it still happened.

have you tried turning the power supply on for a minute before booting the computer

Will try tonight. Also going to reseat the CPU

Regards
Ian

 

[thebigjt]

Hi again

Solved!! It was the config of the M.2 drives in BIOS. I enabled the Hyper M.2X16 and I set M.2_2 PCI config to X4. Set back to defaults and all was OK - chapter 3.6.8 in the manual.

There was never a fault, just a duff BIOS setting.