It’s plugged in and the computer recognizes it but there is no picture. To me that suggests that it is powered up and connected correctly but has failed. I can’t, however, pretend that I know what I’m talking about so I ask you.
I tested it on two computers and swapped in a known good svda cable.
Is there anything else I need to check before I look into the warranty?
With nothing plugged into it (except for the power cord of course), do you see any sort of test image? Is there a button to get an onscreen menu? Does that appear? If neither occurs, the monitor itself is defective.
That old school square profile monitor was discontinued in 2010-2011 so it’s probably a little older than “a few months old”. I would suspect you may have a refurbished unit. It’s a door stop at this point.