/vr/ - Retro Games

I have this Japanese copy of Super Mario RPG that won't keep a save for more than two or three days. When I received the game it had no saves on it at all so I assumed the battery was dead. I replaced the battery with a new one and began playing. Over the next few days I played two or three times and saved without issues. I didn't play the game for three or four days after that. When I went to play it again the save was gone. I tested the battery with a multimeter and got 3.22V. I decided to replace it with another new battery just in case it was a dud, but after three more days my new save disappeared as well. What's really odd is that I checked after one day and the save was still there. I checked on the second day as well and it was still there. But by the third day it was gone. I removed the cartridge from the console after each test, so it's not as though it was being powered by the console.

Does the 256k SRAM itself fail? I checked to see if the SRAM is getting power from the battery and it is. I have a broken American copy of SMRPG that I can take the SRAM chip off of to swap them.