Dragon Warrior Monsters - Corrupted Save? How to fix?

Finally dug out a copy of Dragon Warrior Monsters for GBC I had. Never had a chance to test it till now. Problem is, when choosing continue, the game displays garbage and crashes.

If I play the game enough to be able to save, it shows the save game currently on file as garbage too.

I'm new to using a multimeter, but it looks like I'm getting a reading from the battery. .317, but I'm not sure what setting to have it on.

Anyways, so what are my options? If the battery is good and the save is corrupted, could I just desolder the battery and solder it back on? And if it's dead I just put a new one in of course.

Thanks

 

A good battery is supposed to be about 3v when the cart is not plugged into the system. Assuming you got the meter right, .3 is dead. You should have it replaced. A replacement battery of correct size and with solder tab doesn't cost much but you'd need soldering experience to remove old one and install new one without causing it to explode from excess heat.