HDMI cables are often a issue
I have EMC tested quite a few HDMI monitors and the emissions from a poor cable can be terrible. Easily 10-20 dB over the limits for a heavy industrial machine. Ferrites and such like don't help much at these frequencies so it has to be a well made cable with full 360 shielding end to end with good coupling to the connectors.
Biting the hand that feeds IT
