Not an expert and I am having some weird issues with my Pismo too at the moment, but I think that the button batteries got recharged in it and that is why it stopped behaving like it did before.
I am going to leave mine on the charger for a while and wait until they get recharged. Strangely they are showing power after being dead for like 12 years, and even the main battery the original that came with it got fully charged by this new apple charger I bought off the internet.