Without delay, I popped the cartridge into my N64 and played for a good two hours. A little while later, I turned the N64 on again to continue my adventure but my save file was completely erased! I was very disappointed.
With some work I was able to restore the saving functionality to OoT. In this guide, I will show a method that will likely solve your issue if you are experience the same symptoms as I was.
This guide is not only relevant for OoT, but other games that utilize the battery/SRAM method in saving your games. Read on to learn more.
Some Technical Details about the N64 cartridges:
After I discovered the issue with my OoT, I decided to do some research. What I found is that many of the the Nintendo 64 games (including OoT) utilized a type of memory called SRAM. SRAM stands for Static Random Access Memory. One very relevant characteristic regarding this type of memory is that it is volatile; meaning, that it will lose all its data once power is cut off to it. The RAM in your computer is the same way. All the little processes that your RAM held are lost the second the computer fully shuts down.
However, your game can remember all your achievements, shields, weapons and rupees because it is powered internally by a small coin battery. These coin batteries can last a very long time, but like all batteries, they will die. It's easy to guess that the second this happens, all your saved data is lost.
Another popular method of memory for N64 games is EEPROM, where everything is stored on a little IC and is non-volatile.
If your game uses EEPROM, this guide will be of little use to you since OoT uses SRAM, and the procedure for EEPROM would be much more difficult (or so I would imagine). So how do you know whether or not your game has SRAM or EEPROM? The fact you found this guide actually suggests that you have SRAM. EEPROM chips have a much longer life expectancy than the battery in an SRAM cartridge. If your game does have EEPROM, it is rather unlikely you will ever have issues in saving your games.
Step 1: Obtaining the Appropriate Materials
- Special: A security bit Screw-driver for N64, SNES, NES and GB games http://www.amazon.com/Steel-3-8mm-Screwdriver-Security-Nintendo-Games/dp/B000F8GWH2
- Soldering Iron
- Desoldering braid
- Philips Screw-driver
- One C2032 coin battery 3 volts
- One battery container from Radioshack for the C2032
Step 2: Open the Cartridge; First Test
Use the Philips Screw-driver to remove the metal plate if relevant.
Lay everything out neatly.
Before you proceed; do a quick test:
To potentially save you $5 and a half hour:
Try putting the cartridge back together without the metal plate. Sometimes the way the metal plate, if rusted like mine, interfaces with the circuit board will keep the games from saving properly. It may be shorting the battery out.
After putting it back together, give the saving another shot. If it works, congratulations! Simply continue if not.
Step 3: Removing the Offending Battery
Take a multimeter and set it to Volts, you're only going to be reading 3 volts maximum so you will use a low range. Now set the positive lead against the top pin on the back of the board that is connected to the top of the battery. The lower pin connects to the bottom of the battery. Set the ground lead to this. The voltage across the battery is normally 3 volts. If you are reading 3 volts, this would be bad news for you. This is because the battery is very likely not the cause and the culprit is likely to be the small SRAM IC.
For me, I read a flat 0 volts.
You will now need to remove the old battery. Use a Desoldering braid and remove the solder around the battery posts. Carefully remove the battery from the board.
Take the new C2032 battery and the casing. From the casing, remove the metal clips. Test the negative clip post and insert it into the slot where the old negative post used to be. Your goal is for this clip to be nearly flat. For me I took some cutters and clipped it down so it would fit better.
Before soldering this clip to the board, tape it to the battery, keeping in mind the future position of the battery. This is to help hold it in place.
Important Note regarding your safety: I didn't actually tape the battery to the clip; I soldered the clip on the battery directly. After some additional reading, I found that it is not in your best interest to solder onto a battery otherwise the battery could apparently explode. Here I advise attempting to hold the battery into place first via mechanical means by the battery posts and tape and not by solder.
Now solder the negative post onto the board. Take the positive post and solder that in. The post should grasp firmly to the top of the battery.
Step 4: Clean Up and Assembly
For the plastic and metal pieces, I scrubbed them with some Comet cleaner to remove most of the rust.
Put everything back together and test it out.
Step 5: Conclusions
This was a very happy ending for me: I have my favorite game to play and enjoy now.