Thanks for the input. At first Sony customer service told me to take it back to where I bought it (a local Borders store). Store management said "No, it has to go back to Sony." I shipped it and they returned it Fed Ex overnight

with a new motherboard and battery. So far so good.
Now that I see what a properly working unit is like it is obvious the original battery in my reader had never been able to fully charge, for whatever reason.