My DVD recorder is set to record on video 1. After awhile (variable, hours to days) it stops recognizing audio and instead the tv, when going through the recorder, emits a high pitched squeal. Video, but no audio. If it was always like this I would know I did something wrong. Instead, I do not know if I did something wrong, or if the unit is defective. Has anyone ever encountered this before. And while I don’t know the model number, it is a Sony.