Facing TV Problems? Ask a TV Technician.
Hi and welcome to the site, I’m Louie. Sorry you had to wait awhile but I’ll do my best to help.
Initially, "HDMI NG" displayed message would indicate that the Pioneer's built-in diagnostics has sensed that the HDMI circuitry is 'no good'.
Still, have you considered / tried a RESET ?
Let's try review the basics:
May have to be done a number of times.
This is very critical - a reset however would not be corrective of an internal hardware concern; but it would be confirmed. In some instances, it may even expose/cause other issues.