This is FINAL FANTASY I・II. The internal battery has been replaced with a socket type. Operation has been confirmed. Also, the battery can be easily replaced in the future. However, if you remove the battery during replacement, the data will be lost. Therefore, a backup socket has been added. When replacing the battery, insert a battery into this socket and replace the battery on the board, so the data will not be lost. It is possible to replace the battery while preserving the data without touching any solder. Thank you for viewing.