Computer won't restart from power button after power off

[ffbr]

So I have a bit of an issue, every time I power off my desktop it does not respond to restart command (power button, reset button, power on lan, shorting the power button pin on the motherboard). 

In order to manage to restart it the following procedure need to be applied:

- turn off the power supply

- press the power button for 30s (or wait for the mb to empty its residual power)

- turn on the power supply while pressing the power button of the computer.

 

Doing a clear CMOS usually allows to restart the computer by pressing the power button however at the next power down the same happen. 

 

When the computer is on it works as expected stocked or overclocked. 

 

As I am totally at a loss on that one, I am open to any suggestion. 

 

 

History:

A bit of history on this problem as it as been ongoing for a while and is still present after some component changes and reinstall

It started a bit after adding the CPU to the water cooling loop. 

When installing the waterblock on the CPU, I had to use quite a bit of pressure as the backplate was not stock and the screws slightly too short. I observed when changing the motherboard that the IHS is slightly scratched on one corner (don't know if it could be relevant)

 

At the time the motherboard was an x470 aorus ultra gaming and it was a different power supply.

After reading that it could be a problem with the power supply I changed it with another unit that I knew was in good health (no change)

I then proceeded to change the cmos battery, after a bit of hope the problem appeared again 

As I needed to update my boot drive I also changed it (no change).

I also tried to disable fast startup, swap ram with other modules I had around (also tried single channel)

Did all bios update and such

Tried without any header in the motherboard (sound, usb, fans)

As I was really not happy with the VRMs of the motherboard and am planning for a gen 4 high core count I proceeded to change the motherboard, I had a bit of hope but the problem return after maybe 5 reboot without problems)

 

As I was really annoyed I also tried to set up wake on lan, which worked once.

 

What I did observed is that sometimes it would not restart even after turning off the power supply. In that case, removing all usb peripheral allows it to restart using the described procedure)

Sometimes letting the computer powered off for long (24h) it will restart on a button press (but not all the time)

 

I have also seen sometimes that the PC still appears as available in some socket processes after power off.

All this makes me wonder if the PC does not stay in some kind of active state.

 

 

Summary of steps taken:

- change of motherboard

- disable fast startup (windows 10)

- change of boot drive

- change of RAM

- try to use wake on lan

- windows reinstall

- linux install

- bios update

- chipset install

- CMOS battery change

 

Current components :

- Motherboard: X570 tomahawk

- CPU: ryzen 5 2600

- GPU: vega 56 (msi aero)

- RAM: corsair vengeance LPX 2*8gb

- Disk: WD blue SN550

- PSU: seasonic prime 1200 platinum

 

 

 

 

Edited June 12, 2020 by ffbr