Question PC randomly disconnects everything(monitor, keyboard, mouse) but PC is still on.

[rohith_jain]

I have a strange issue. Recently, I updated BIOS to version 5220 on the Asus ROG Strix X470-F motherboard. Now, PC randomly disconnects everything but all components are running (CPU fan and LED, Case fans, RAM LEDs, GPU LEDs, Mobo LEDs and also standby power led on mobo). But I cannot power off using the case power button. I have to pull the plug to shut it down.
Motherboard: Asus ROG Strix X470-F Gaming
CPU: AMD Ryzen 7 2700X
GPU: MSI GTX 1070Ti Gaming
PSU: Corsair CX 650
RAM: Corsair Vengeance Pro
SSD: ADATA SU650

Tried Solutions:
Clearing the CLRTC and resetting the CMOS battery.
Flashing the older BIOS version.

Can anyone please help me with the issue?

 

[Ralston18]

Do you use Windows shutdown before you physically turn off the case power?

If not, it is very likely that the sudden power losses are corrupting files. Always use the Windows shutdown icon first.

Check the motherboard's User Guide/Manual to understand what any lit LED's are indicating.

Open the case and ensure that all cables, components, RAM, jumpers, etc. are fully and firmly connected. Check the case power button as well.

Clean the case of dust, debris, paper scraps, dead bugs and so forth.

That said, what about the PSU: how old is the PSU? New, refurbished, or taken from another computer?

 

[rohith_jain]

Do you use Windows shutdown before you physically turn off the case power?

If not, it is very likely that the sudden power losses are corrupting files. Always use the Windows shutdown icon first.

Check the motherboard's User Guide/Manual to understand what any lit LED's are indicating.

Open the case and ensure that all cables, components, RAM, jumpers, etc. are fully and firmly connected. Check the case power button as well.

Clean the case of dust, debris, paper scraps, dead bugs and so forth.

That said, what about the PSU: how old is the PSU? New, refurbished, or taken from another computer?

How can I shutdown using windows if I cannot see anything on my monitor and no power supply to keyboard or mouse.

PSU is an year old. It was a brand new PSU when I bought it.

 

[Ralston18]

You can however boot and shutdown normally if the computer has not crashed and disconnected in the meantime - correct?

Does the computer run for at least some amount of time before the disconnect occurs?

Use that time to check Reliability History.

You may also be able to run "sfc /scannow" via the command prompt to identify and fix any corrupted system files.

As for the PSU - even new PSUs can be defective and start to fail prematurely.

 

[rohith_jain]

You can however boot and shutdown normally if the computer has not crashed and disconnected in the meantime - correct?

Does the computer run for at least some amount of time before the disconnect occurs?

Use that time to check Reliability History.

You may also be able to run "sfc /scannow" via the command prompt to identify and fix any corrupted system files.

As for the PSU - even new PSUs can be defective and start to fail prematurely.

"sfc /scannow" had some corrupt files. Fixed the corrupted files using DISM. Reliability History has no issues. I even replaced the CMOS battery but nothing seems to work. I got the mobo from USA and bought the PSU here in India. I can claim warranty for PSU if that's the issue but not for Motherboard(no global warranty for ASUS). But, I guess I have to give them a reason that it is indeed a PSU issue.

 

[Ralston18]

Do you have a multimeter and know how to use it? Or have a family member or friend who does?

What you can do is test the output voltages to determine if any are out of spec.

Here is how to test:

https://www.lifewire.com/how-to-manually-test-a-power-supply-with-a-multimeter-2626158

Not a full test as the PSU is not under load. However, if a voltage is truly not within the stated range that would be a reason to return the PSU.