Good that only batteries at fault. I just recalled I heard the same screech sound a second time, I then put my CJ MV55 into service as replacement, never did go back to NEW. I bet batteries may have been the only problem for guy I sold it to these many years later.
I never did hear the full potential of NEW, it was in one of my early systems, curious as to how it would sound in my present system.
One common misconception about the NEW is that it was Nelson Pass design, it was in fact only Pass influenced design. I purchased mine in 1996, interesting design, and how I learned about how dirty AC affects sound quality. I actually went to in home audio dealer intending to purchase VonSchweikert speakers, came out with NEW.