Many of my older NiMH batteries started to fail. My camera sucks a lot
of power Minolta F300, and on vacation my newest batteries were terrible.
An older set worked much better. I have yet to buy more batteries, but I
bought a good 8 cell individually controlled charger for about $50. In
using
this charger I was able to find the best ones, that had reasonably low
impedance, and I threw out at least 2 dozen of my mostly older cells.
Make sure the contacts are clean. I usually try to put something like
Deoxit
on the batteries.

greg




My guess is that the batteries that work are a hair longer or have a
slightly different shaped end than most batteries and they've bent the
contacts so they no longer mate correctly with most of the ones you try.