t's a great time to be a Goozex member. Having recently expanded their repertoire to include DVD, Blu-Ray, and HD-DVD movies, they also now include classic games from older systems. A problem you may face with older games, though, is the battery backup. Between passcodes and flash memory, battery-backed saves were the way to go. Using a watch battery was a very good solution to saving your progress given the small amount of current needed and the extensive life a watch battery provides. These days you may be testing your old library to send them out on Goozex, or you just got one in that you've been looking years for only to find that it doesn't save. With a little work, though, the cartridge can be back in good working order.
First, double and triple check your game. Are you turning it off appropriately? In the original NES, most games' instruction manuals insisted you must hold the reset button while turning it off, or risk losing all of your memory. Also, just like the PlayStation era, don't mess with the power when you think it may be saving. Make sure you're in general gameplay screens when you turn off your system. Once you confirm that the game isn't saving, flip it over.
In the case of the Nintendo cartridges, you will find three screw holes. On a Game Boy game, you will find only one. On older games, you may get lucky, as this particular copy of Zelda I operated on actually had flathead screws in it. Soon, Nintendo transitioned to special screwheads. The simple way to remove these is to purchase a gamebit, which can be obtained through eBay for about $5. Another solution is to find a cheap Bic pen (the kind with very brittle plastic that shatters easy). You can warm the plastic up a bit and jam it down on the screwhead. It will mold to the shape of the screw, creating your own homemade gamebit. Or, you can do like I did on my Gameboy Donkey Kong.
I took my power drill and buzzed shavings off around the edges until I could get my needlenose pliers in around the screw to pry it out (insert copious amounts of Tim Allen grunting here).
Once you crack your game open, locate the battery. It'll be the large round disc with two prongs on the outside of it.(anyone else as amused as me to see "Sony" emblazoned all over the chipset?)
There are prongs soldered on the battery. With a pair of needlenose pliers, pop the prongs off of the battery, making sure of two major parts: 1) remember which direction the battery is seated in the cartridge, and 2) be careful as to not pull the prongs out of the board itself.
Next, determine what size of battery you need. The battery number is emblazoned on the positive side of the battery. Inside this particular copy of The Legend of Zelda was a CR2032, and inside my Game Boy Donkey Kong cartridge was a CR1616. It is best to get the same number, however if you can't find it, don't give up hope: talk to someone in the Wal-Mart jewelry department where they replace watch batteries: they helped me look for a different battery that had the same voltage, but a longer lifespan. The only problem with changing batteries is the physical shape of the battery may not fit back inside the cartridge. The CR2016 had the same voltage as the 1616, so it would have worked, but it was too big for the space. Watch batteries change, though, so there may be different options when you visit the store.
Once you get the battery, you have a couple options. You can use a soldering iron to reconnect the battery, but any solder in a wrong place on the circuit board could destroy the game. It also makes the new battery permanent, which makes it harder if you ever have to replace the battery again. Personally, I chose electrical tape. Place a piece of electrical tape underneath the bottom terminal, flattening it out as much as possible (it may have gotten bent up during battery removal). Put the new battery in, and fold the other terminal on top of the battery, then tightly wrap the electrical tape around the battery. You can also place a roll of electrical tape inside the cartridge case where the battery faces the plastic to add a little pressure to squeeze the terminals together. The downside of the electrical tape solution is while an average person without a soldering iron can do it, if you don't ensure the terminals are secure, one wiggle on the battery could reset your memory again. Make sure the terminals are as flat as possible and making as much contact as they can with the battery.
Once you are sure that the terminals are secure, snap the cartridge back together. Nintendo games have a set of tabs on the top you lock in before swinging the lid back down, and Game Boy cartridges have a tab slide/lock system. Prior to screwing the bits back in, put the game in your system and do a test. If you can, put some screws with matching threads into the screw holes, so you can leave it for a day or two to test the longevity of the save. Once you are sure it's back in top working order, screw the specialty screws back in, and enjoy!