Mark and Seth, thanks for the very good suggestions. I'll check those out. Just reading these posts makes me realize just how much I don't know -- and should.

Mark, I tried fiddling with the switch (half position) but couldn't cause a failure.

Wow, I just looked over the info on the SR Batteries site (as well as the rcbatteryclinic site) and I have to say I'm totally overwhelmed! Man, and people say my dissertation is hard to understand!!!