Fired up my GT-8 to practice and tweak some settings and got an lcd message "battery low". Checked the manual and found nothing on how to change it other than to send it to a dealer. No way. Next time I fired it up got an lcd message "factory resets or programs". Shut it off immediately in hopes I hadn't lost many hours of dialing in sounds. Took the back off and found the battery, but can't see any way to take it out. Afraid to pry on it, etc. HELP !!!!!!!!!! HOW DO YOU CHANGE THE BATTERY?