PC in continuous restart, FML!

[Tongs of Destiny]

Ok this is weird.

PC will run 24/7 perfectly fine. Maybe this all started after a power failure a while back, I'm not 100%. But today, PC was running 24/7 perfectly.. then we had a power trip. I turned everything off at the wall and waited. Now the power is back on again... When I start the PC it goes into a continuous power loop, on for 5 seconds (not even enough time for the screen to come on) then off... then on.. then off... then on... then off.. It did this yesterday as well. After fiddling and resetting a million times, it then just decides OK I'm fine and turns on and runs normally?!

I've changed PSUs, RAM, HDD, GPU..

Any ideas?

 

[RedViking]

I would take a guess and say mobo is damaged.

 

[Scooby_Doo]

Ok this is weird.

PC will run 24/7 perfectly fine. Maybe this all started after a power failure a while back, I'm not 100%. But today, PC was running 24/7 perfectly.. then we had a power trip. I turned everything off at the wall and waited. Now the power is back on again... When I start the PC it goes into a continuous power loop, on for 5 seconds (not even enough time for the screen to come on) then off... then on.. then off... then on... then off.. It did this yesterday as well. After fiddling and resetting a million times, it then just decides OK I'm fine and turns on and runs normally?!

I've changed PSUs, RAM, HDD, GPU..

Any ideas?

Only other options you have not tried, motherboard and cpu, most likely motherboard.

No motherboard lights or beeps on the reboots?

 

[Jet-Fighter7700]

stupid question here, power short on the case?
had something similar before, took me years to figure it out, eventually removed the screw holding the bracket of the GPU and everything worked,

 

[adam_g]

PC seems to be failing its POST

try removing RAM if you have more than 1 stick remove 1 and test remove 1 and test
if you have a GPU unplug and remove that also
remove all your drives nvme, SSD, HDD
i would say remove your OS drive as the constant on and off may cause the OS to corrupt
do this all 1 by one so you can find the culprit.
Also unplug your keyboard, mouse, speakers, headset etc etc
Generally, if it's the motherboard the PC doesn't turn on at all but there is still a possibility that it is the MB.

 

[Tongs of Destiny]

No motherboard lights and no beeps, on power on its runs through 4 LED's and as you think its normal, click.. turns off, then back on again.

No shorts, as it has been running perfectly for months. In fact it was perfect until we just had a power failure.

@adam, ive changed the RAM over from the other PC and still no change.

What's weird is when it eventually decides to get going again, it will run perfectly for days.
It's like something is telling it to turn off on the MB.

I even changed the MB battery yesterday, still no change.

 

[Scooby_Doo]

No motherboard lights and no beeps, on power on its runs through 4 LED's and as you think its normal, click.. turns off, then back on again.

No shorts, as it has been running perfectly for months. In fact it was perfect until we just had a power failure.

@adam, ive changed the RAM over from the other PC and still no change.

What's weird is when it eventually decides to get going again, it will run perfectly for days.
It's like something is telling it to turn off on the MB.

I even changed the MB battery yesterday, still no change.

Tell me more about the "click" is it an audible click? Try to build the PC outside the case to eliminate shorts.

 

[Tongs of Destiny]

ok solved : well for now.

So I'm running 2 graphics cards, in 2 power supplies. I unplugged the cable from the GPU to the PSU and it boots up no problem. I then plugged the cable back in and it restarts again... I then swopped position on the PCI-E input on the PSU and it still restarts.. I tried say 3 slots and it restarts on all of them.. the 4th attempt at a different PCI-E location and it works all perfectly now?

Very weird... maybe something inside the PSU is not happy?