Hi there. We do in fact offer game cartridge battery replacement! We're able to solder new batteries in to GameBoy, NES, SNES, N64, and Sega Cartridges. Just give us a call or check out our site for more info!
They do in fact replace the save batteries, and for pretty great prices. Their website has price lists online for their various services. There's a "mail-in repairs" price list, and an "in-store repairs" price list. Dropping the games off in person is cheaper than via mail, but even mailing in is pretty cheap. They also do bulk pricing if you're getting above a certain number of repairs all at once. I haven't sent in any cartridges for repairs myself, but I've shopped there several times and can say that the venue is very professional and trustworthy.
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