I have a 124 G on which I can't remove the battery compartment cover! It's just plastic and I don't want to damage it so, since the needed cell is or would be a mercury cell, I just rely on a hand held meter. Nice cameras, aren't they!
If you don't have an instruction manual, http://www.butkus.org/chinon/yashica...24g-splash.htm has one for downloading. Send Mike Butkus a little money so he can keep up the good work.