Changing Batteries in a NES Game

Quite often you'll hear people asking about how to change the battery in their old NES games. The batteries in these games are getting old and you hear about batteries going dead more and more.

Although, a lot of forums discuss the topic, I could not find too many good tutorials out there, so I've decided to put this one up. Using this method, you don't need to be able to solder and you don't need the "Security Bits" that you will hear people talking about..

ATTENTION: If this is your first time, don't expect your end result to look as good as mine. I've done this hundreds of times and have gotten quite good (IMHO). So take your time and do your best. Also, it may be a good idea to start with a game that you already have an extra copy of ... Just in case something goes horribly wrong.

You should read through the WHOLE tutorial before you start. I am not responsible for any damage you do to your game. Use of this tutorial is at your own risk and you should follow proper safety measure whenever using tools or video games.

Step 1. THE STUFF

To change the battery, you'll need a few things, similar to what I've pictured here.

At any time during the tutorial if you want to see a larger photo, simply click on the one provided.

Now, since I don't have any games that need new batteries, I'm going to show you how to add a battery to Super Mario Bros. Once you know how to add a battery to a game, changing those batteries is a simple matter.

Some of the equipment you should have on hand: Game (of course), pliers, crowbar, hammer, extra hard drive (6 GB or larger), pen, breadboard, Multimeter (Make sure it has a DC Voltage setting!), electrical tape, cordless drill, dremel and of course BATTERIES!

Step 2. GETTING INTO THE CARTRIDGE

Unfortunately, Nintendo used special screws to hold their carts together. Most people will tell you that you will need a security bit to unscrew them. But, what they forget, is that there is really no need to unscrew them. To get your cartridge open, start by using a cross-cut saw (Do not use a rip saw as we will but cutting ACROSS the grain of the cartridge)

If you notice an odd smell during the cutting, this is normal. Basically it's the particles of the plastic reacting to the heat caused by the friction of the saw blade rubbing across them. Another option to access the cartridge is to turn the blade around on your skill saw and use that, however, that is beyond the scope of this tutorial.

Once, you've created the first cut, you can use the crowbar to begin prying apart the cartridge. When driving the prybar end of your crowbar into the cartridge be sure to strike it at an angle proportional to the ratio of your cartirdge width/crowbar length, otherwise you may find that you damage your crowbars paint job. As you can see in the photo, I've learned this from experience.

Once you have the crowbar inserted you can use the hard drive for a fulcrum to apply leverage to your cartridge. If your cart is still together, move on to Step 3, otherwise you can skip right to step 4.

This is probably already going better than you thought!

Step 3. WORKING ON THE BACK NOW

Those screws can still cause a problem, so you may need to go a little further. As you can see in the photo, I've resorted to drilling out the screws.

If your drill isn't as large as mine, that's OK. Size doesn't matter when it comes to these screws. By drilling all the way around the screw, you'll find that the back will snap right off.

Step 4. LOOK NO GAME!

That's right, for a game like, Super Mario, the actual printed circuit board (PCB) does not go all the way up into the cartridge. This is what gives us the room to add the batteries.

If the game your working on does have PCB right up into the top, than you should really stop and think about what you are doing before you continue.

Step 5. FINISHING THE OPENING

Now all that's left is to remove the bottom portion of the cartridge so we can access the PCB for our battery connections. Using a pair of snips you should be able to open it up no problem. Just take care that you don't overuse the snips and you will eventually put this cartridge back together and you want it to look like it did when you started.

With a good mod, you can't even tell that the mod's been done.

Step 6. ATTACHING THE BATTERIES

Now that we have the cartridge open, it's time to attach the batteries. Before you attach them though, you should check them to make sure they are still good. Believe me, it sucks when you get it all back together only to find out that it won't work due to bad batteries.

Although my batteries were supposed to be 1.5V, they are reading 1.6!!! It's a good thing I checked! I threw these batteries away and found some. This is not a game of inches, it's a game of micrometers. Make sure you do everything EXACTLY!

In this photo you can see how I've attached the batteries using "Electrical Tape". If you don't have "Electrical Tape" you can use another kind.

Once you have the batteries in, don't forget to attach the positive of one to the negative of the other. If they are not connected they will not work in "Synergy".

Part 7. WIRING

Now that the batteries are physically attached you need to wire them together. Please note that in the photos you will see I am also adding some CAT-5 cable. You can safely ignore that as I am also adding broadband capabilities to the Super Mario Bros., but that is well beyond the scope of this tutorial. The red wire is where the batteries are attached to each other.

Now that they are attached to each other you need to connect the + end of the battery pair to the "Positive Battery Connection Pin" (PBCP) and the - end of the battery pair to the "Negative Battery Connection Pin" (NBCP).

Note that I am not using solder at any time, however, you could if you wanted to.

Par 8. PUTTING IT BACK TOGETHER

Now that the cartridge has the batteries added and is function, we need to put it back together so that it is clean and no one will know that we've been inside.

I've started by using wood glue to attach the top back portion. IMPORTANT: Make sure you attach the top to the top and the bottom to the bottom, otherwise the cartridge will not fit into the NES anymore! I can't tell you how many times I've seen this happen to inexperienced modders.

I'm using black "Electrical Tape" to attach the bottom as I find it is less noticable than duct tape and shields the cart from electrical interference from the NES system.

Note that there is no real way to hid the broadband cable of course, but yours should look pretty much like it did when you started.

Step 9. ENJOY!!

Now that the cart has been successfully modded you can enjoy Super Mario Bros. with it's new battery capabilities anytime you like. The first time you load a saved game your friends are sure to be stunned!

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