Question Help, Onboard Video Not Working

[Mulsiphixx]

Hardware Involved

• I built three computers with identical hardware, identical cloned Windows drives, but one of them has a GTX 1660S (HDMI 2.0b port). The two using on-board video (Asus Prime X570-P, manual) connect via a HDMI 1.4b port.
  
  
• I have a Samsung 226BW monitor (DVI-D port utilizing a DVI-D to HDMI converter).
• I have an Asus Pro Art monitor (HDMI port).
  
  
• I have two HDMI cables (one bundled with Pro Art, the other claiming Hi-Res 1080p 3D support).

Behavior Observed

1. The 1660S worked with both HDMI cables and monitors. The on-board video PCs do not show video with either monitor, not even during POST, but sound confirms they boot into Windows successfully.
   
   
2. The Samsung has a source switch button to go between VGA and DVI-D. When on VGA it says I should check the cable for issues. When on DVI-D it flashes between an Analog and Digital message a couple of times, seemingly searching for a signal, and then the screen goes purely Black with no error about the cable at all.
   
   
3. The Pro Art immediately reports there is no HDMI signal detected when I plug the cable in and then the screen goes purely Black.

My Question
On-board, it seems an HDMI signal is not being detected. With two motherboards sharing the issue, I doubt the HDMI port is faulty. Seems the issue originates with the motherboard, but I'm not sure how to further diagnose this problem. Anyone have any ideas on what I might try next?


Additional Information
I checked the manual and on page 8, the only place it mentions anything about HDMI, it states:

Integrated Graphics in the 2nd and 1st Gen AMD Ryzen with Radeon Vega Graphics Processors

VGA output support: HDMI port

- Supports HDMI 1.4b with max. resolution 4096 x 2160 @ 24 Hz

 

[Mulsiphixx]

I have confirmed that the motherboard only supports APU's, not CPU's like the Ryzen 5 3600x I have installed.

 

[UsandThem]

I have confirmed that the motherboard only supports APU's, not CPU's like the Ryzen 5 3600x I have installed.

In the Asus Prime X570-P?

I'm not sure where you read that at, but that board accepts standard Ryzen CPUs (like the Ryzen 3600x).

https://www.asus.com/us/Motherboards/PRIME-X570-P/HelpDesk_CPU/

 

[Mulsiphixx]

In the Asus Prime X570-P?

I'm not sure where you read that at, but that board accepts standard Ryzen CPUs (like the Ryzen 3600x).

https://www.asus.com/us/Motherboards/PRIME-X570-P/HelpDesk_CPU/

Whoops. I meant that the "onboard video" is only possible with an APU installed in the system. That a CPU and a monitor hooked up to the HDMI port on the motherboard will not provide a video signal.

 

[UsandThem]

Whoops. I meant that the "onboard video" is only possible with an APU installed in the system. That a CPU and a monitor hooked up to the HDMI port on the motherboard will not provide a video signal.

That is true.

The "GPU" part is on the CPU, so if you don't have an APU installed, the video ports on the motherboard will do nothing.