My TUF B760M-Plus WiFi II motherboard won't pass POST without a monitor attached

[dch53]

Hi. 

I had this problem where my previously-working new PC wouldn't pass its POST; the VGA Q-LED was staying on which according to the ASUS documentation I found online, suggested a problem with the graphics card. Since my CPU had on-board graphics the recommendation in the ASUS documentation was that I replace the CPU. I reluctantly tried that and the result was the same.

I took the PC to the place I bought all the components and they found no problem with it. It turned out that the problem was a dodgy HDMI cable AND that the motherboard won't pass its POST without a monitor attached.

Is this normal? 

I was advised I should buy a USB HDMI emulator if I want to use the PC as a headless server.

Anyway, I now have an expensive spare CPU. Fortunately, I have an old PC that needs updating.

Thanks.

[Jiaszzz_ASUS]

Hello @dch53 

Thank you for reaching out to us.
Based on your description, it appears that this new build initially booted correctly. Could you clarify what specific software or hardware changes occurred before the issue you’re describing began, such as a BIOS update or changing with another HDMI cable?
After your setup was tested at the place of purchase, were any additional findings or recommendations provided?
With the VGA Q-LED indicator lighting up and failing to boot, this suggests a detected display signal issue during the POST process, which could indeed involve cable or monitor-related anomalies.
Could you please confirm the specifications of your current HDMI cable and if testing with other HDMI or DP cables was able to boot properly?
Additionally, may I ask if you have the specific requirement to operate the PC without display output?

Thank you.

[dch53]

Hi and thanks for replying. Once I swapped HDMI cables the PC booted perfectly.

To repeat my original question, is it expected that the motherboard won't pass POST if there is no monitor connected? I don't understand why anyone would want that behaviour.

Is there a BIOS setting to change that behaviour?

If the PC had been for me I would have been using it without a monitor. Fortunately, it's for someone else and they will be using a monitor.

I have to say that throughout this process I found the difficulty finding the right ASUS documentation frustrating.  Both with this problem (and the recommendation that I needed to replace the CPU) and the difficulties I had setting up RAID.

Links from the very brief and basic user manual for Q-LED debugging and RAID setup would have saved me a lot of time and money.

Regards, Dave.

[Jiaszzz_ASUS · Accepted solution]

Hello @dch53 

POST is primarily used to check for hardware issues in your hardware devices before the BIOS loads the OS, ensuring the PC functions properly.
Based on your description, we can only speculate that the HDMI cable might be faulty, which could have been detected during the POST process, preventing the system from booting successfully.
Generally, when there’s a lack of a connected monitor, you may encounter the VGA Q-LED indicator lights up and the system fails to boot.

Regarding the RAID configuration, the TUF GAMING B760M-PLUS WIFI II supports SATA RAID 0/1/5/10, and you can refer to the steps outlined in [Motherboard]How to create Intel 600 or 700 series MB RAID in BIOS Setup for more details.
If you have any concerns about the setup, please share the specifications of the SSDs currently installed, their slot positions, and any error messages or descriptions of issues you might be encountering.

Thank you.

[dch53]

Thanks. I have to say that I am puzzled why you'd want a  computer not to boot if there was no monitor attached.  I've built a number of computers for use as headless servers over the years and I've never come across it.