It’s a little known fact that some game cartridges use batteries for storing saved games, so if your game stops saving then the chances are that the battery inside the cartridge is dead.
Changing the battery is fairly easy if you have the right tools and some basic soldering skills.
Tools Required
You will need a 4.5mm or 3.8mm Security Screwdriver Bit to open the game cartridge.
A Soldering Iron and Solder Braid or Suction Pump.
Replacement Battery Types
You will need a CR2025 battery with pre-soldered tabs,
For the Game Boy Advance you will need a CR1616 Battery
Accessing the Circuit Board
Remove the single screw from the back of the cartridge using the security bit and remove the circuit board from its plastic housing.
Replacing The Battery
The battery is soldered to the circuit board via two tabs. Heat up each tab and use your solder sucker or braid to remove the old solder. Then solder the new battery into place making sure that you match the polarity to the one you have just removed.
Finally
Reassemble the cartridge and your ready to play and save your games for the next five to ten years….