Radio will be on but no sound from speakers. Why?! on 2004 Nissan Quest

It used to be the radio would be on then suddenly there was no sound from speakers. Sometimes a loud popping or distorted sound would come out then no sound at all. But it still showed the radio on and working fine. Now the radio will not even come on at all. I read it could be the amp. There was a TSB about no sound but radio on.

Asked by for the 2004 Nissan Quest