Does the Casio FX-451 have a battery? Or is it strictly solar?

From: Michael Craft
Email: mcraft@udri.udayton.edu


I have a Casio FX-451M. Iíve owned it since 1985. A *GREAT* calculator. Anyway, I have always thought it was strictly solar powered. But Iíve read in a couple places that thereís also a battery. Is this true?? Should I replace it? How? Do I simply pop the metal plate off? Also, does anyone have a copy of the manual for this calculator? Thanks