I have the same problem (6 year old TSU-9600 with failing battery) and was wondering if you've received any advice or figured out how to replace the battery. I understand that dissassembling this this is pretty difficult/challenging, but I'd be willing to attempt it if I had some good instructions on how. Or, alternatively, if someone could recommend a reliable place to send it to to have this done (though being w/o it for a time will be an issue for me).