A short while ago, a great friend of mine purchased a used Super Metroid SNES cart. However, he quickly realized the SRAM battery was shot, which meant the cartridge could no longer save his game. I offered to see if I could swap the battery for a new one and give back the cart is functionality.
The first obstacle, I knew, would be the darn tamperproof gamebit heads used by Nintendo to keep their cartridges shut. I had a piece of scrap aluminum around, and on the second attempt managed to file a passable makeshift gamebit driver. (For my first attempt, I made the miniature spokes were too thin; because aluminum is so soft, the tool quickly bent out of shape.)
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| Makeshift hand-filed gamebit driver. |
Fortunately, the cartridge screws are only very lightly tightened, and my improvised tool made short work of them.
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| One down. |
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| One screw out of the cartridge. |
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| Unfortunately, the tool lightly scratched one of the screwholes. |
Then came time to have a look at the goodies!
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| Freshly-opened cart. |
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| The culprit, a dead CR2032. |
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| Look at that battery. As Shijima said in Ninja Scroll: a strange technique! |
The CR2032 is held in place using a manufacturing technique I'd never seen before. After some research, I realized that you can purchase so-called tabbed CR2032 batteries which come with such tabs preassembled. The tabs look like they're cold-welded to the battery casing in two spots; I presume this is done before the battery itself is even assembled, because it looks as though the welds on the bottom were made from
within the battery. The spots form a tight bond between the battery casing and the tabs, and it took quite some effort to separate them.
At this point, seeing as how it looked as though I would have to irreversibly deform the tabs when removing the battery, I decided to turn to the internets to see what others thought the best repair method was. I found a few blogs pointing to the following page:
http://motherboard.vice.com/en_ca/blog/pictures-how-to-replace-an-snes-cartridge-save-game-battery
I thought: tape is an obvious solution, but surely a permanent battery holder would be a much better one! And I happened to have one lying around from a discarded PC. I removed the old battery and tabs, and tried the battery holder for fit.
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| Removed tabs. |
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| Trying the CR2032 battery for fit. |
Unfortunately, though it was elegant, this was not meant to work. I quickly discovered there is not enough space inside the cartridge case:
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| FAIL! Not enough space inside the cart. |
Luckily I hadn't soldered the holder in place yet. I simply removed it, soldered the tabs back in and taped the battery as suggested. The new battery holds quite fast, and I preloaded the tabs with tension so the battery mostly holds in place even without the tape.
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| Tabs back in. |
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| Battery in place. |
I then closed everything up and tested the fix. Victory!
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| Closing up the case. (The soldering job looks terrible in this picture; it doesn't look nearly as bad in real life.) |
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| Testing out the fixed cart with my furry assistant. |
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| The galaxy is at peace! |
Edit: seems there was possibly more to this cart's problems than the battery, since it just suffered another saved game reset. To be continued...
Second edit: many thanks to reader Kincl, who pointed out that Super Metroid is apparently an ornery cart whose SRAM/battery circuit is difficult to restore to health! It appears this is a somewhat common case:
http://www.racketboy.com/forum/viewtopic.php?f=17&t=44493&sid=02d23a1f277a5b503e4a9004b029cbe4&start=0
For what it's worth, this specific cart has held up for just about a week now. Time will tell how durable the repair ultimately was.
