Weird issue: PC “revives” itself after 24h – no power no leds until 24 hours after

[Megahackerd]

Hello,

Currently my system refuses to turn on, no sign of life, no leds except when i press the bios flashback button, which then starts up, updates the bios (with the usb) and then shut down.
The dead pc goes on for 24 hours, and then it magically starts working, no signs of anything wrong, passes benchmarks, stress test, works for days, until i need to turn off the power and unplug from the mains to move/work on the computer, then the 24 hour cycle starts up again.

Any ideas of what is wrong?

I have tried 2 different power supplies, both which pass the fan test and work with different computers.

Specs:
Lian Li Vison Chrome
Lian Li Galahad LCD
Montech 1200w, and Lian LI SP850w (just one plugged in at a time)
Amd 7800x3d
Gigabyte B650 GAMING X AX V2 (Rev. 1.x)
32GB GSKILL DDR5
Zotac 4070 Super




I believe the motherboard is faulty, but Gigabyte refuse the RMA as it is an USA motherboard

 

[mickyflinn]

Hi.

When you say dead pc are there any power lights on the motherboard ?

Power led

 

[Megahackerd]

Hi.

When you say dead pc are there any power lights on the motherboard ?

Power led

Nope no lights at all.

The only reaction I get is when I press the bios flashback button

 

[VaderDSL]

Dodgy cmos battery?

 

[darkblade]

Dodgy cmos battery?

This!

Replace the CMOS battery with a new one and go from there.

 

[Megahackerd]

This!

Replace the CMOS battery with a new one and go from there.

Nope does not work.

It has been 24 hours and it worked straight away.

Turn off the plug, and turned it back on and didn't work again