How to replace a save-game battery in a cart without erasing info

[atarilovesyou]

Guys, I'm thinking of swapping out these batteries in many 20+ year old NES carts (and others). The thing is, in some cases I don't want to erase the information stored in the games.

 

Shouldn't there be a relatively easy way to maintain continuity while swapping out the old battery? Connect them in parallel, perhaps? Or would it require an external voltage source connected directly to the cart (no idea how to do that, mind you) while you remove the old battery?

 

Thanks for the help. It wouldn't be the end of the world if I lost some save games, but damn...some of this stuff is like personal history

[icemanxp300]

http://nintendoage.com/forum/messageview.cfm?catid=22&threadid=133957

[Skippy B. Coyote]

Though it might be a much more expensive solution than you'd like, the Retron 5 does have the ability to store save files from your cartridges on the system's memory then transfer the save files back on to your carts after you've changed the batteries. It's an option that doesn't require any technical expertise to pull off, but the price tag may make it a "last resort" solution.

[Andromeda Stardust]

You could use a doner CR2032 battery with wires and an inline resistor (10k should do). The inline resistor prevents reverse current flow into the old battery. There are gold solder pads on the back of the nintendo board that correspond to the (+) and (-) terminals. Solder in the wires to the donor battery on these pads, then replace the old battery with a new one. Lastly, remove the donor battery. You also may consider placing a holder in the cart for future battery changes. The cart will typically retain data for 30 seconds or more without a battery, until the circuit capacitance gives out. Be careful not to short the positive and negative battery terminal during a transfer or you will lose the data.

[atarilovesyou]

You could use a doner CR2032 battery with wires and an inline resistor (10k should do). The inline resistor prevents reverse current flow into the old battery. There are gold solder pads on the back of the nintendo board that correspond to the (+) and (-) terminals. Solder in the wires to the donor battery on these pads, then replace the old battery with a new one. Lastly, remove the donor battery. You also may consider placing a holder in the cart for future battery changes. The cart will typically retain data for 30 seconds or more without a battery, until the circuit capacitance gives out. Be careful not to short the positive and negative battery terminal during a transfer or you will lose the data.

 

 

...hmmm, 30 seconds, eh?...maybe if I was super quick on the switch? My luck I'd mess this up

 

Thanks for the suggestions. Cool feature for Retron 5...if it were only a bit cheaper!

[Andromeda Stardust]

 

 

...hmmm, 30 seconds, eh?...maybe if I was super quick on the switch? My luck I'd mess this up

 

Thanks for the suggestions. Cool feature for Retron 5...if it were only a bit cheaper!

Unless you are Superman or can shoot laser beams from your eyes to heat the solder, you aren't going to desolder the old battery and have a fresh one installed within 30 seconds. The save may well stay intact longer but mileage may vary, hence my recommendation to use a second donor battery to maintain voltage at all times. An electrolytic cap precharged to +3V should also hold a charge for long enough period of time to erform the transplant.

 

Retrode is another good backup device for SNES/Genesis as well as a few add-ons for other systems (N64, SMS, GB/GBA). It can dump the ROM as well as read and write save files. uSadly it's been discontinued so the Retron5 is the next best thing.

Edited August 6, 2015 by stardust4ever

[icemanxp300]

Unless you are Superman or can shoot laser beams from your eyes to heat the solder, you aren't going to desolder the old battery and have a fresh one installed within 30 seconds.

 

I want to take that challenge. I only have battery holders but I could just use a similar dead battery I have removed or for that matter the same battery. I think 30 seconds would be feasible especially if the holes cleaned out but if not you could always just heat them and push the new leads through. You can pop an old battery out in like 10 seconds, then just push a new one in drop on some solder and be done.

[MaximRecoil]

If you have the game powered on while changing the battery, you won't lose your saves. There are various ways to do that, but the easiest way is to disassemble the console enough so that you can plug the bare cartridge PCB into the card edge connector, turn the console on, then change the battery. I doubt this would feasible with a front-loader NES, because of the awkward positioning and the lack of a standard card-edge connector, but it works fine with an SNES (I did it last night), and I see no reason why it wouldn't work fine with any other top-loading console.

[bohoki]

i would probably take a 2aa batt holder and solder on red and black (parallel) replace the battery and then remove it

 

but i would only change it when i noticed it so it would be too late in my case