sit down, take a breath and start again.
Offhand, it sounds like a conversion/scaling problem but without more info, not too much I can say.
What type of input are you using on the TV? Composite, component, HDMI or what? What's it's resolution?
What is an S/D bell receiver and how do you have it connected to the NAD? Composite, component, HDMI or what? What resolution is it outputting?
As for that "525/60 signal" message, I'm totally lost. Is that generated in the TV or the receiver? You might want to check your manuals for a translation.