Correct that to say "ANY GOOD 600 to 750 mah pack.."

With that, I totally agree.

But, I bought one of the original DX7's and, although I never experienced the "brown-out" that some did, I immediately switched over to 6 volt ( 5 cell ) NiMh packs so that I would never reach that threshold unless I was sleeping or something...

Thus, I have a box full of older 4 cell packs that I have absolutely no idea of their status

CGr.