The main board battery (used to save the clock settings) is number 414. The battery is spot welded to the base strip on the board (-), and the battery’s top (+) is spot welded to the + tab that’'s folded over the battery then connected to the board. There are fine connections from the + tab to the board. While the battery can be removed using a razor (very carefully), the + tab is glued to the board and soldered to the + leads of the board. If not “very” careful you can break the + tab away from the board. If your hero does not retain its clock settings, then that battery is dead.