Changing the Battery in a Nintendo Game Cartridge
Posted by aaron cepek
Nintendo Game Battery Replacement Guide
This is how I changed the battery on an nes cartridge and somehow managed to salvage the save data. There are kits that may make replacing the battery easier. You assume responsibility for damaging your game by attempting these instructions.
What you will need:
- 3.8mm bit security tool
- CR2032 battery
- electrical tape
- pliers
- exacto knife
- wire
Optional Materials
- soldering iron
- solder
- ohmmeter
I read through the battery replacement guides over at the 9th Key as well as DarkBubble’s guide posted at GameFAQs. Both give a lot of good tips and use slightly different methods. Check them out for some further information. Also follwoing the guide is a short list of links to eclectic NES knowledge, mods, and homebrew information.
First, gently remove the screws. Don’t strip them. Get the WD40 if they are rusted. I have read there are other ways to open a cart if you don’t have the proper tool (heat, pressure, beguilement). I can’t imagine any of them working very well (for me at least). I looked around and couldn’t find any locally, so your best bet is to get the 3.8mm security bit online .
Next remove the circuitry and locate the battery. It’s pretty obvious. If your game saves but you can’t find a battery then the NES game you have is magical. Hold onto it.
If you have an ohmmeter you could check the old battery to see if it is in need of a change. If you have an extra ohmmeter you could give it to me. Next pry the battery from the clips to which it is welded. I used an Exacto knife and pliers. Be careful not to damage the nearby chips. I used the Exacto to make enough room to grab the clip with the pliers. I then sort of peeled the clip off. Whatever works.
I then stripped the shielding off of the end of some speaker wire. I am sure lots of different types of wire can be used. Just be sure that the metal portion of the wire will not touch any other surface (keep the bare contact portion minimal). At this point you can use the electrical tape to attach the wires to the battery or solder it. Either way try to keep from touching the surface of the battery too much (so that their is less resistance for the current).
I soldered the wire to the battery here, but it was not easy for me. It was my first soldering project. I found the best method to attach the wire was to actually solder over the top of the wire while holding the wire to the battery. This isn’t really true soldering (probably) but it was the only way I could get it to work without getting the battery extremely hot. Besides degrading the life of the battery it is supposedly possible to get the battery to explode. Hot acid. No thanks.
Once you have the wires attached to the sides of the battery it’s time to attach them to the metal clips on the board. Make sure to get the positive and negative wires sorted out. The negative is towards the outside in my experience. It should be printed on the circuit board if you forget. Soldering these wires is much easier this time. If you aren’t soldering just make sure to wrap each wire around the proper clip well.
Once it’s all in place cover any metal surface that could short out the circuit with electrical tape. Replace the circuit board into the notches in the case. I then taped the battery to the side of the cart to keep it secured and less likely to come loose.
That’s it. It should work great now. The amazing thing about the Final Fantasy cartridge I worked on was that the prior saved game was still in the memory after I changed out the battery. There must have been enough electricity stored in the memory to hold it for the half-hour the project took. I can’t guarantee it will keep your old save files, but there is some hope if you work fast!
NES Links
In my researching of this project I came across some eclectic NES knowledge, mods, and homebrew information that would interest any geek:
- Interesting NES console modifications
- Game Development for the 8-bit NES A class by Bob Rost
- NES info, programs, and demos
- The 9th Key’s NES battery changing guide
- DarkBubble’s NES battery guide posted at GameFAQs
- The Nintendo Repair Shop
Good Luck!
Try something spontaneous.
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