How To Change An NES Game-Save Battery

 Whether you would like to admit it or not, lots of our retro gaming equipment will slowly die off. While Nintendo cartridges might be pretty durable, you might not realize that the batteries needed to save progress and scores don’t last forever.

When a battery dies, you will lose all your gave saves and high scores and will not be able to save any data again until you replace the battery. So maybe you should stock up on batteries and do your renovations now.

I have pieced together some information from various online resources (mainly this guide), so i thought I would share them here as an easy reference. Also, if you have any additions and/or corrections, please let me know so I can update this.

DISCLAIMERS: YOU WILL LOSE YOUR SAVES WHILE DOING THIS, NO MATTER WHAT! I take no responsibility for your messed up games– this is a risky procedure — you should practice on something cheap and easy to find (like Dragon Warrior or Ultima Exodus) before trying this on your gem mint Final Fantasy or Dragon Warrior IV cart.

What You Need:

  • 3.88 mm security bit. You need this to unscrew the funky hexagon-shaped bolts on Nintendo carts.
  • An NES Game Battery
  • A basic soldering iron, nothing fancy. I bought a kit at radioshack for $8, came with a 45-watt iron. (You COULD also just tape the battery in instead of soldering)
  • An X-Acto knife, or some kind of scraping razor. It justneeds to be a VERY thin knife, one you don’t mind getting stained up. A kit with a variety of blades can also be found at Radioshack, Wal-Mart or craft stores, for around $4.
  • Some Electrical tape.
  • Pliers

NES Game Battery Swap Walkthrough

  1. Clean your hands thoroughly first.
  2. With your NES cart lying face-side up on a table, you’ll see the two hexagon bolts on the bottom two corners. Use your 3.88 mm security bit to remove these bolts.
  3. Lift the cart’s front cover by pulling up, toward you. You’ll see thebackside of the game’s board. Lift the board out. Try not to touch anythingbut the edges any more than you have to.
  4. On the other side of the board, you’ll see the battery on the top left corner, a silver circle about the size of a nickel. The battery is soldered onto connectors above and below, at two points on each connector. The next step is to break these solder points (carefully!)
  5. Remove the battery from the board. The battery is held to the board by two clips which are soldered to the board. (You can see these clips in the photo. The soldering iron is pointing to one of them.) Turn over the board and heat the solder until you can open the clips (i.e., bend them away from the board). Be very careful not to hold the soldering iron to the board for very long! If the board gets too hot, you can ruin the chips. After the clips are bent up, let things cool down.
  6. Now you need to remove the clips from the battery. This can be a tricky step, because the clips are spot welded to the battery. A soldering iron will not help remove the clips. You’re going to have to pry the clips off. My tool of choice for this is an X-Acto knife. Use an old blade, because it will be ruined.
  7. Insert the X-Acto knife between the spot welds and “cut” into the weld. Be very careful! This is very dangerous. I suggest using a vise to hold the battery, or you risk badly cutting your fingers. The welds should pop off after some struggle.
  8. Once the clips are removed, you have another tricky step. What I do is melt a small amount of solder onto the battery (long clip goes on +), then hold the battery and clip together with a pair of pliers. I remelt the solder while squeezing the pliers. Be careful NOT to heat the battery! It can explode or leak acid, which can cause injury. Repeat the procedure on the negative side. Make sure the clips are aligned properly.
  9. Once the clips are back on, we can put the battery back on the board. There should still be plenty of solder around the clip holes to work with. Make sure you have the + and – correctly aligned. Place the tip of one clip over the hole, and melt the solder from the other side. Again, be careful not to heat the board too much. When the solder melts, the clip should poke through. Bend the clip back into place.
  10. Place the board back it into the back cover of the cart and place the front cover of the cart over this.
  11. Replace the 2 hexagon bolts. If the board still rattles, you might need to tighten the bolts down a bit more. If you taped the battery in, it’ll probably be a snug fit.
  12. Pop the game into your NES, play long enough to save. Turn the machine off, take the game out and throw it around. Tap it on a table, drop it, rattle it, be rought with it but don’t break it! This is just to test how secure your battery is in there. If you plug it back in and still have your save, congrats. Chances are, your battery is secure for the next 10 years.

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One Comment

james harmon says:

I got 10 batteries from you I wish you tell me how to solter the battery without pins on battery .you said they could taped tell me where on the board do you tape thanks

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