Replacing the Battery in a Game Boy Cartridge

History:

Due to extra circuitry to enable a real time clock, the battery inside the Pokemon Gold & Silver Game Boy Color games have a tendency to run out of power after a few years. Once this happens, you are no longer able to retain a Saved Game. This is a guide that I posted [here] at the Pokemasters.net message boards in January 2007 to teach people that it was possible to fix this problem by replacing the battery.

Can your Pokemon game still hold a save?

If your Game Boy game is no longer able to hold a save, yet can still be played fine, that most likely means that the battery in the game cartridge has run out of energy.

You can easily replace this battery, restoring the cartridge's ability to store save data. This replacement can be performed for much less than the cost of buying a new game. You just need to purchase a new battery.

**Basic soldering skills required**

Materials:

Soldering iron

New 3 Volt Coin Cell Battery - CR2025 (165mAh) or CR2032 (220mAh)

Adhesive tape

Fine tipped hemostat or needle-nosed pliers

Flip over your cartridge.

Locate Screw

Using a hemostat, needle-nosed pliers, or anything else that you can grip it with, unscrew this little screw by turning counter-clockwise.

Once the screw has been removed, turn cartridge over, slide the front cover downwards, and pull it off.

Now you can see the circuit board, and the battery that allows one of the chips to retain the game save data.

You can see that both Pokemon Red and Silver cartridges look very similar, except that the Silver circuit board has a crystal oscillator in the upper left-hand corner to control the passing of time in the game.

Now that you have the cartridge open, take a look at the battery and the circuit board where it is attached.

You can see that the type of battery used is printed on the board above the battery. For my Pokemon Red and Silver games, the CR2025 coin cell was used. I went to a Radio Shack store to buy my replacement battery. Instead of using a CR2025 battery, I chose to install a CR2032.

The cartridge needs to use a 3 volt battery that fits in this position. The CR2025 has a storage capacity of 165 milliamps per hour (mAh). The CR2032 is also 3 volts, but is 220 mAh so it will last longer. It is 0.7 mm thicker than the CR2025, but since there is some extra room inside the cartridge it still fits.

Take note of the polarities of the battery. The wider side, which is facing the board, is positive (as specified by the + on the board). The side that is less wide, which is facing you, is negative (as specified by the - on the board). Remember this, as you will need to make sure you connect the new battery the same way.

Remove the Old Battery:

**Warning: Use caution when working with a soldering iron! If you touch any metal that is connected to or touching the tip, you will be burned. Only hold the iron by its handle. Do not touch the battery's tabs with your finger right after you unsolder them, as they may still be hot. The battery itself may also be hot if it is in contact with the soldering iron for an extended period of time.**

Basicaly, use common sense. If you aren't confident in your ability to handle a soldering iron, find someone else who is.

To remove old battery, you will need to unsolder the contacts where the battery's tabs connect to the circuit board.

**Warning: Do not allow solder to touch any parts of the circuit board other than the pad where the tab is connected. If you create a connection between any of the traces on the board, you may end up ruining your game.**

Once the soldering iron has heated up, touch it to one of the mounds of solder where the battery's tabs are connected to the board. When the solder melts, use some pliers to pull the battery up so that the tab pulls away from, and is not in contact with the board. Repeat the process with the other tab to fully remove the battery and its tabs from the board.

Inserting the New Battery:

Now that the dead battery has been removed, you can install the new one. If you get a battery that already has tabs attached in the right position, this will be the easiest replacement. You can just solder the tabs to the board in the same position as the original. (The positive (+) side is facing the board, with the tab pointing to the upper left. The negative (-) side is facing upward, with the tab pointing to the bottom right.)

The following section that is in italics tells how I had originally instructed to connect a new battery since I did not have a new one with tabs already attached. As you can see in the updates, you can end up killing the battery if you try to solder to it. If you want to take the time to try to make a spot welder, you can attach your own tabs to a new battery.

If your new battery does not have tabs in the same positions as the original battery, you will need to reuse the original tabs. By gripping the tab with some pliers (use ones with small or no teeth so you don't destroy the tab) you can pull it off of the old battery. Once you have removed both tabs, straighten or flatten them so that they are in the same shape as they originally were.

To save yourself a lot of wasted time and effort, don't try soldering the tabs onto the new battery. My Dad and I both tried to do that with the new battery I got, but whatever kind of metal or coating it had, the solder would not stick. It may just be that the metal battery dissipates heat too quickly for it to heat to the temperature that the solder will bond to it. If you did try to heat it to that point, it would most likely explode. The one that I had looked like it was starting to bulge from the heat.

Take the flat tab, and solder it to the board's positive (+) contact in the position that it was in when it was connected to the first battery. As you can see in the picture of my Silver cartridge's battery, I placed the battery in place (wider side downwards) and brought the solder up against the side of the battery to make better contact.

Next, place a piece of tape on the side of the battery near the negative (-) contact. You should probably do this before putting it in place. This will keep the negative tab from touching the wrong contact as the bend allows it to lay on top of the battery.

Now solder the negative tab to the pad on the board so that it bends upward and lays flat across the top of the battery, making electrical contact (the tab's metal touching the metal top of the battery).

Place a piece of tape over the top of the negative tab to hold it to the top of the battery.

When you place the cover back onto the cartridge, you want it to press on the battery to hold it in place so that the pressure keeps the tabs pressed against the battery. If you use a CR2025, it will be thinner then the CR2032, so you will need to add a kind of spacer (such as some more tape or folded up paper) on top of the battery until you can feel the cover pressing tightly when you put it back on.

Once the battery is being held tightly, slide the cover back up along the grooves in the sides, so it stays closed, and screw the screw back into the hole to hold everything together.

**Warning: If you open the cartridge again after you have saved a game, you may lose your save file since the pressure of the cover is what was keeping the tabs in contact with the battery. If that contact is lost, the game will be reset.**

Congratulations!

If you followed these instructions correctly, and didn't solder on the wrong places, you should have a working game that can now store a save file while it is turned off! Now when you play, you don't always have to start at the beginning again!

NOTE: The fresh battery must be connected firmly to the board. If one of the tabs looses contact, you will loose all your Save data.

Update:

When you install the new battery, make sure that you don' t try to solder directly to the battery. I was trying to play Silver recently, and the game save data was corrupted because the battery wasn't connected well enough. I tried a few different things to connect the battery better, but by the time I got the tab connected well to the battery, it had died from too much heat. The soldering iron can kill the battery it you heat it up too much.

I took the old battery out, and now I am trying a different approach to connect tabs to a new battery. I have made a kind of arc welder by taking apart a flash that you would put on top of a 35mm camera. I connected wires to the capaciter, so that when I touch both of them to the battery and tab, the electricity makes a flash, melting them together. Sometimes this works, sometimes this doesn't. I just need to find a place where I can get the tab to fuse firmly to the battery so I can put it in the game cartridge without losing a connection.

Update:

If you can find a battery that has tabs it will save you a lot of trouble in attaching your own. You can buy them online (part number P223-ND at digikey.com) if you want to pay a lot for shipping.

You can also find battery holder clips that you can solder to the cartridge and then just put the battery in it. These clips are the kind of thing you may see holding the CMOS battery on a computer motherboard. You would just have to make sure it is thin enough to fit in the cartridge.

If you don't want to spend a load of extra money buying batteries with tabs, you can build an spot welding device. This will work much better in attaching tabs to your new battery than trying to solder it.

If you have a disposable camera (or any kind with a flash that you won't mind taking apart), you can open it up and make your own welder.

• Find the capacitor inside that stores the charge to power the flash.
• Attach a wire to each lead of the capacitor.
• Use an insulated tool such as pliers to hold the tab in place. If it isn't held down, the spark may make it fly off the battery.
• Once the capacitor is charged up, place one wire touching the edge where the tab meets the top of the battery.
• Touch the second wire to another point where the tab touches the battery.
• Remove both wires.

When the second wire makes contact, a spark jumps between both wires, melting the spots where each wire touched the metal. This allows you to fuse the tab to the battery. If you practice this, you can get it to work. Sometimes you get a stronger hold than others, so make sure you fuse multiple areas where the tab touches the battery.

I covered the tabs with epoxy to add extra strength.

Now your battery should be ready to solder back onto the circuit board.

Update:

I have finished soldering the battery, with its finished tabs, back onto the circuit board. I have tested that it successfully supplies 3 volts, and I have played it for a while to verify that the saves are sustained.

The most important thing to remember when replacing your battery:

Make sure that there is a firm connection between the battery and the board at all times.

My first replacement battery was ruined by trying to solder tabs onto it. If your battery does not have tabs already connected, find a strong method of connection such as welding the tabs on or using a battery clip made to hold the CR2025 or CR2032.

Good luck to anyone else who tries to replace their battery. If something doesn't work, keep trying. You will eventually find a solution.