Gameboy Cartridge Battery Replacement

I recently picked up a few new (to me) Gameboy Color systems and a few games to give away as gifts over the holidays - Pokemon! While checking the games out I noticed that none of them had, or could, save games. I learned that Nintendo, the geniuses that they are (literally), put in coin cells into their game cartridges to forever power their RAM chips to allow players to save their progress. Now that a lot of these games are over 15-20 years old, the batteries are starting to fail. Watch this video to see an easy way to change them:

Start by opening the cartridge. There is a single screw in the back with an unusual head. The driver for it is called a GameBit, and they can be found for pretty cheap on Amazon here: Gamebit on Amazon

If you don't want to buy one, like me, you can actually make your own by either heating up the end of a plastic pen, or in my case, using a piece of a ruined 3D print. The idea is that you will use a lighter to heat the plastic until its soft, and push it into the head of the screw. It will mold around it and harden, leaving the perfect tool for the job.

Once the screw is removed you can slide down the cover of the cartridge and it will come off. You will be able to see the battery at this point.

Mine was 18 years old! Check the battery for voltage, if its dead, replace, if not, replace anyway because its going to die. Oh yeah, you're going to lose your save game when you remove the battery, sorry... If you can figure out a way to keep power to it while you desolder it, then it might stay, but I don't explain how to do that in this.

Put some flux on one of the connections of the battery and heat it with your soldering iron until it comes loose and lift it up, repeat for the other contact until the battery is removed. Simple!

Take your new battery and find the correct polarity. There are markings on the battery, and on the board, so it should be easy. Again take some flux and put it on the contact pad. There will likely be enough solder on the pad where you won't need to add any extra. Connect both sides and clean off the flux with some isopropanol.

Check the battery voltage again, you should see around 3V.

You're done!

Enjoy playing your classic games again without the thought of waking up one morning and all of your progress is gone!

Go check out my YouTube for more (usually much more intricate) open source electronics projects! youtube.com/seanhodgins