Question No signal on my monitor

[Amathy]

Components I had the problem with
-Z790 Asrock/Z690 Asrock Phantom itx (with biosflash for the newest update)
-NZXT 750w/Corsair SF750
-MSI 1070/Gigabyte 4070
-2 Corsair 32GB
-I5-13600kf

I tried both GPUs on multiple ports with 3 cable, and I know the hdmi works for sure.
I tried all ram slots ins every configuration possible.
Red indicator lights go on while booting but quickly off again( I think that is how it is supposed to be).
All fans and lights are on and visually there is no problem. I think I can even go into windows.
The signal goes lost along the way I guess and I would really need help identifying which one.

If you need any more clarifications please let me know

 

[Ralston18]

Make and model monitor?

What connectivity?

How was "I know the hdmi works for sure" determined?

On the host system: any error codes, warnings, or informational events in Reliability History/Monitor or Event Viewer?

"Red indicator lights" - which lights? Check the motherboard's User Guide/Manual to determine what the lights are for and what the color and the meaning ("quickly off again") may mean.

 

[Amathy]

Make and model monitor?

What connectivity?

How was "I know the hdmi works for sure" determined?

On the host system: any error codes, warnings, or informational events in Reliability History/Monitor or Event Viewer?

"Red indicator lights" - which lights? Check the motherboard's User Guide/Manual to determine what the lights are for and what the color and the meaning ("quickly off again") may mean.

My monitor is 34inch hpx34
I tried the HDMI cable with a laptop and the x34 monitor. To be sure I tried out 2 DP cables too.
Shortly means 5seconds the Dram and about 10 seconds the boot and vga one. But the manual says if it goes off it should be fine.
I had once the problem with getting a black screen when booting into windows.
Before this, I could get a signal on the old ATX Mobo on the 2nd Pcie slot with hdmi and only the 1070. So It might be an x16 issue.