Unable to save progress on N64 cartridge

I have an old Super Smash Bros. cartridge for the N64 (that I purchased recently). I am unable to save any progress for the game.

I have done some research and all of the online information says that the battery needs to be replaced. I have done so (more than once) by soldering the battery in. There is a brand new battery that has been checked with a voltmeter and is outputting (slightly over) 3 volts.

I have also found information indicating that the battery might be getting shorted out by the metal casing surrounding the board. I have insulated the inside of the casing with electrical tape, placed the board with a new battery face down in the casing and verified that the battery is not being shorted by the casing.

Despite all of this, the cartridge is still unable to save progress (I have been testing it by doing the Bonus 1 Practice for Mario, completing it, checking that the fastest time is displayed, turning the console off and back on and then trying to verify that the time is still there). A friend of mine has suggested that it might be an issue with the SRAM but I can't find any information online ever mentioning this as a potential problem, much less finding anything else that might help me fix whatever is causing this issue.

Any suggestions or tips would be greatly appreciated.

Solution 1:

I've your battery is replaced and fully charged then the issue is most likely that the circuit which feeds that ROM chip isn't getting sufficient power.

I would look into replacing the capacitors on the board. Think there's only one or two.