Phillips Magnavox 60P8241:

The other day i turned on the TV and i get no sound or any raster. I looked in the back and i can see the heaters for the CRTs glowing, and i can hear high voltage scream. I repair arcade monitors for a living, so i can rework PCBs and read schematics. But i have never working on a projector before, so i am lost. My best guess is that one or more of the guns are bad. So how do i test the guns? Are they worth replacing? I see a lot on this forum about problems sound with no picture, but i dont have either :( If anyone can help that would be great!