I'm trying to replace my old (still working) AMD motherboard with a new one with a J5040 cpu (and an IT66317FN retimer) onboard but I'm not able to make it communicate with my old Samsung 4K IPS TV. So far I've been able to the get a hdmi signal only using a low-res vga-hdmi adapter. With LE10, using xrandr, I've been also able to see a fhd screen in the upper left corner of my TV screen set in 4K resolution. I upgraded LE to version 11 but the situation didn't improve.
I'm aware it should be an hardware issue, but I wonder if someone could be so kind to suggest what to try in order to solve the problem.