Z790-H Stuck on POST

[antionioteto]

Hello,

I have a serious problem with my motherboard.

My specs are:

Z790-H

i7-14700KF

Gskill Trident Z5 2x16 GB 7200MHz CL34

RTX 4070

Samsung 980 Pro 1TB

PSU Be Quiet pure power 12 850w

Before i got the ram i flashed the board with the latest bios available(1801) in order to be compatible with the 14th gen cpus

After i got the ram i enabled the XMP I profile (it booted to bios with default settings) and it wouldnt go past the post screen and the green boot qled was on.

I pressed the clear cmos button and i got into the bios i selected the XMP II Profile and everything worked fine. I ran a memtest for quite a while and there were no errors.

After this i installed win 11 did all the updates for the drivers etc using the Armoury crate software i used the pc for some hours with many restarts and shut downs in order to check if the system is unstable at boot.

Today i restarted my pc and again it didnt post. But now the problem persists even with default settings. The clear cmos button doesn't work and the only way to do it is by unpluging the cmos battery. The system boots into safe mode in bios and then when i restart with any setting(restore system defaults or even on safe mode with no changes) it is frozen on boot screen with the green boot qled always on.

Things i tried:

Use only 1 ram stick

Use both on A1/B1 slot or switch positions on A2/B2 as i originally installed them.

Reseat the CPU(looked carefully for any bent pins fortunately there were none

Use another RAM kit(again a 7200mhz tridentz kit)

Unplug all power cables from the motherboard and the cmos battery

Used another PSU(Corsair HX 1000)

Use another slot on the m2 drive, used a different m2, use no drive at all

I rolled back to two different bios verions(1501, 1402) 

The problem remains the same the systems boots in safe mode and after restart it wont post and the boot qled stays on and the cpu fans are on 100%

I thought maybe i got a bad cpu but after some research i found that others have the same problem with me

What should i try or do from now on?

Thank you for your time

[Silent_Scone]

Hi @antionioteto 

Are you able to use USB flashback to 1402 and tell me if the behaviour is any different before troubleshooting further? Try and report back.

[antionioteto]

Hello,

I got to a point where i figured out that this happens when i disconnect the pc from the power source eg.  unplug the psu.

Then my system will freeze in post screen for a couple on minutes with the boot qled on as before and after this it will boot like nothing happened 

What might be the cause of this?

I will try again to flash the bios version you said and i will get back to you

[HappyShabbat]

After you realized that the symptoms are influenced by unplugging the PSU, did you then try the HX 1000?

The  PSU is the most frequent error source in any electronic system.

Unplugging the PSU often means your system will get colder because of the lack of standby loses. You can check the temperature of your system in BIOS setup.

Metals shrinks when they get colder. If you have poor connections in a plug, then you will risk loosing the connection if the plug cools down below a certain level.

Did you disable quick self-test/enable advanced test in BIOS?

Also observe that you can unplug the SSD and boot a minimal Linux (no install required) from an usb key or boot it from a small partition on you Samsung SSD. Then you can run a stress test. 

[Jiaszzz_ROG]

Hello, @antionioteto 

Based on the situation you've described, we recommend referring to the troubleshooting guide [Motherboard] ASUS motherboard troubleshooting via Q-LED indicators to verify if the green Q-LED is indeed the boot indicator and following the steps provided.
Additionally, please check the section "Test with minimal components, isolating the possible cause" in  [Motherboard] Troubleshooting - No Power/No Boot/No Display.
If necessary, we recommend cross-testing with different CPUs.

Thank you.

[antionioteto · Accepted solution]

Hello,

It seems that the issue was the first m2 slot on the motherboard(the cpu powered one)

I installed the nvme on another slot and it works almost fine except some times it takes a little bit to boot but its ok.

Otherwise the system is pretty much stable with no other issues.

i didnt had the chance to install a different cpu to check if the issue persists or with another nvme drive