HDMI Issues (Xbox One S)
If you are having HDMI issues there are a few causes.
If your TV displays Invalid Format and no screen this is due to the output resolution/format not being supported by your TV.
Turn off the console, then hold Eject and Power while turning on for several seconds until you hear a second beep after the first power on beep (or just continue to hold both until the console fully powers up then off again).
This will reset the TV resolution to the universally supported 640x480 by default.
Often this is the actual HDMI port is bad, or the EMI filters coming off the data lines, or the retimer chip itself.
Inspect the HDMI port for damage, and check every pin is well soldered and not shorting. If in doubt, swap the HDMI port.
Check the EMI filters all have continuity through them, but not to any pins to the left or right.
If both of those are good I would suspect the retimer chip. So it is worth swapping out.