Borrowed from racketboy.com :
What You Need:
SNES Game Battery Swap Walkthrough
- 3.88 mm security bit. You need this to unscrew the funky hexagon-shaped bolts on SNES carts.
- A SNES Game Battery (aka an CR2032)
- 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.
- Clean your hands thoroughly first.
- With your SNES 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.
- 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.
- 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!)
(Edit: I have found that my copy of Final Fantasy 3 has 4 solder points
on each side, but all my Nintendo made games have only 2. YMMV.)
- If you plan on soldering for the best connection (otherwise, skip
to part 8), plug in your soldering iron, wait for it to heat up(it’ll
change color when it’s done.) Set your razor against it, for a minute
or 2. Slide the hot razor between the battery the top connector, push
it against the first solder point. You will need to find a safe and
comfortable position to push from– you will need a bit of leverage, but
also be careful of your fingers and chips on the game. Be VERY patient–
with enough reheating, pushing, and some cutting, the first point will
- You have two choices– either repeat the process on the second
point, or attempt to “wiggle” it loose. If you choose to wiggle it, be
very careful not to snap off the connector or bend it completely out of
shape. A little bending is fine.
- For the bottom connection, cut the first connection the same way
you did the first. For the second connection, wiggling is less risky
since it’s the last one, but still be very aware of what you are doing
and be patient. Each game is soldered differently, so make your best
- Either solder the New battery back on if you know how or tape it
into place. To tape it, take a 2 inch piece of tape and place it under
the bottom connector. Place the battery in between the two connectors
and wrap the tape around it as tight as possible. You can even double
up the tape, to make sure the battery won’t go any where.
- Turn the board back over (battery-side down) replace it into the
back cover of the cart. The slots it fits into are arranged so you
won’t be able to re-insert it upside down, so if you’re having trouble
putting it back in, turn it over!
- Place the front cover of the cart over this. Remember the hooks
that slide into the back cover? They make it so you have to angle the
back cover down & away from yourself. 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.
- Pop the game into your SNES, 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.