Tendo City

The Great Work begins.

I've bought a lot of battery holders and Maxell brand replacement batteries for this, and have started to replace all my battery backed games with fresh ones, along with battery holders so the next time around it's far easier.

(I picked Maxell because they have a proven track record.  Plenty of my NES games STILL hold their saves.  That's good enough for me.)

The first step was taking a multimeter and tracing out, on each type of cart, where a good place to set up a secondary battery would be.  I lost a few saves in the process, but their sacrifice is not in vain.  I'm pretty adept at spotting the patter now, just following the lighter parts of a PCB to the nearest pin and soldering an extra wire onto that.  (I clip off the legs of a resistor for these, since they're nice and still and won't move around on their own.)  I actually have just left the legs on.  I then stick a spare battery in a spare battery holder and alligator clip the legs of that holder to my "spare" pins.  It's important to do this in parallel, not serial.  Once that's done, I desolder the existing battery.  It's taken a lot of practice but I'm getting pretty good at this part now, and can get the old battery out pretty quick.  The new one is a little tricky.  The slimmer "negative" pin isn't quite slim enough, so I have to clip it down a little, but then it fits fine.  Add a little flux, and the solder flows in and grips it very well.  Once the holder's in place, I slip in a fresh battery and finally unclip the emergency battery.  Seal it up, and it's ready to test.  I lost two big saves at first, but now I know just where I went wrong and am avoiding those errors going forward.  I've got battery holders in Link to the Past and Ocarina of Time now along with the same classic saves I've had for years.

Gameboy games are going to be tricky.  So so small...

I've been meaning how to learn to do this with NES games. Less to back up saves, so much as... be able to save to begin with. I bought an NES with Star Tropics about 3 years ago. I put it down in frustration, because twice, I lost my game save, after putting in hours. And yes, I was turning it off properly. I made sure of that. But some 12-24 hours later... poof, gone.

Unfortunately, I don't have basic tools, like a soldering iron. Maybe I'll pick one up at some point, if laziness and apathy don't keep me in their grips. It never occurred to me that I'd have to do the same with N64 games. Balls.

The good news with the N64 is that on the N64, "only" controller paks and certain titles have batteries; most games with on-cart saving have other types of non-battery flash memory chips.

However, the list of games with batteries in the carts is most all major titles -- F-Zero X, Smash, Ogre Battle 64, OOT, etc...

Let me give you both a few tips for soldering. First, get a decent iron. No barn burners.

https://www.amazon.com/KSGER-Temperature...3420091698

This is a very high quality one for the money, with a dial for the temp. If you get it, a good temp to work with is 375 C if you do it quick (high temp, low time).

Now then, you'll want solder. .015 inch rosin core leaded solder should do fine. Yes, lead, so take precautions. It's just easier to work with then non-leaded. Use a face mask, or get a fume extractor. Either way, if you aren't soldering constantly the exposure is so minimal you don't really need to worry about it.

Get a "no clean" flux pen. That flux is going to save you a lot of frustration. A little dab will make the solder stick to metal far easier.

These irons usually come with a sponge. Get a wire sponge instead.

https://www.amazon.com/Hakko-599B-02-Wir...7999&psc=1

This one. I put a few big heavy washers in the bottom of mine to keep it from sliding around when I use it. Trust me, "water" sponges are awful, and no one really uses them. Dry metal sponges are far better.

Alright, when it comes time to remove the solder on the battery pins, first add solder. It's counterintuitive, but remember this is really old solder. It's oxidized a little, and the chemistry isn't quite the same as what you likely bought. So, mix in a little of your own. Once the solder on a pad melts into a little pool, just pull the battery up on that side nice and easy. Now do the other. Once it's dropped out, you'll lose the save pretty much instantly, but the new battery should last you another 30+ years so that's fine. Apply some flux to the battery tabs on the new battery, then melt the pool again and slide the first tab into the hole, then pull the iron away. The pool should cool down in about a second or two and then repeat on the other. There, you've got yourself a new replacement.

This is a good starter if all you want is to get a dead battery changed out. When you're ready for the next level, let me know and I'll describe the extra steps involved in adding a battery holder while keeping your old save file intact.

Oh, and the memory card in the N64 uses a battery too. That can be backed up easily enough with a Gameshark to hold it while you do the thing. It's pretty nice. There's also a trick to remove the SMD chip and replace it with a model of the chip that isn't volatile and holds the memory. That's pretty advanced though, involving either a "spade" style long soldering wedge, or a hot air station.

That is helpful, thank you! I'll make a project out of it at some point. I did a bit of soldering in shop class in high school, so hopefully that'll help.

This is my solder station.. Not as cool with all the digital readouts. But has a lot of nice features.
[attachment=370]

https://www.amazon.com/gp/product/B07HQN...UTF8&psc=1

I like the fact that the guns turn on and off when you pick them up as well. It's a nice feature to this digital rework station.

That's something like what I have. The hot air blower is a nice feature. I was listing a cheaper one without it though, as a good starter.