Now to connect the new battery onto the PCB. In this guide, I've used a CR2032 Battery Holder designed for use with any and all Nintendo cartridges. However, you're free to use a standard CR2032 battery with pins already attached to it. A battery holder will make future replacements easier.

Place the new battery in the same position that the old battery was in on the PCB.

NOTE for Battery Holder users: You may need to modify the holder slightly. Take note of the second image in this step. One of my cartridges resistors was placed very close to the battery and resulted in it blocking the placement of the holder. If you're in a similar situation, you will need to file off the corner of your holder as shown.

With the battery in place, begin to carefully heat up the terminal and the batteries pins.

I use the word "carefully" in the literal sense. Heating up a battery is universally NOT a good idea, but all you need is just enough heat that the replacement solder will flow on to the pin properly.

Once the terminals and pins are hot enough, begin applying a generous amount amount of new solder to the space between the pins and the terminals.

Once you're done, you should have something that looks like the third image in this step.

Let the solder cool off after you're finished. Test the terminals with your Multimeter to make sure everything is still operating normally.