I have a Sanyo 30" HDTV and also an ATI HDTV Wonder. Until yesterday both worked find with WGRZ (NBC) but as all of you already noticed not my TV show only black screen.
What is really strange is that my HDTV PC board still work fine and show a really good signal strength comparing with the signal from a few days ago (not it is around 80-82% comparing with 36-38% last week)
I hope that WGRZ will fix this ASAP ... I don't like to watch TV on my computer...

Maybe they are trying to switch to full power... or fixing the frequent image freeze ... who knows...