I’d posted this on the PVB Discord server about a week ago, and someone encouraged me to make a post about it here.
Vague Rant was reverse engineering and making patches for much of the VB’s game library last year, and discovered that the Japanese version of Golf (T&E Virtual Golf) contains code for a save feature. Despite this, retail carts of the game shipped on a cartridge PCB without a battery on it, and the code falls back to the password system you typically see in it.
I wanted to see if I could get the save system to work if I transplanted the JP Golf ROM chip into (in my case) the PCB for a spare JP copy of Teleroboxer. My experiment succeeded!
Some important things I need to point out:
– This only works with the Japanese version of Golf, since the SRAM code is completely dummied out on US cartridges.
– You need a donor SRAM cartridge to transplant the JP Golf ROM chip into. Should you choose to also transplant the donor cart’s ROM chip into the PCB from Golf, you can play it, but it won’t save any of your progress. Consider this a destructive mod for the donor game!
– I recommend using either Teleroboxer or Galactic Pinball as a donor, since they’re fairly cheap and common. The only other SRAM cart options are all rare and/or expensive: 3D Tetris, Wario Land, Virtual Fishing, and SD Gundam Dimension War.
– Soldering knowledge is a must. I would not say this is a beginner-friendly mod, sadly.
– Transplanting the ROM chips requires some special equipment, either a hot air rework station (used in this guide) or low-melt solder like Chipquik. Moreover, you need to remove TWO chips to do this mod. Practice it on some scrap electronics if you haven’t already done something like this before.
Tools required:
– Japanese copy of T&E Virtual Golf
– Donor game with SRAM on it (used in this guide: Teleroboxer)
– 3.8mm game bit screwdriver
– Soldering iron
– Tool for SMD chip removal (hot air rework station, or low-melt solder)
– Tweezers
– Solder
– Desolder wick
– Solder flux (highly recommended)
– Kapton tape (not required, can be helpful)
– Isopropyl alcohol (90% or higher)
– Q-tips
– Tabbed CR1616 battery (same as for a Game Boy game)
I don’t have any low-melt solder and as such can’t give any specific advice for how to use it for this mod.
Directions:
1. Disassemble both cartridges with the 3.8mm game bit screwdriver. Take the two PCBs and move the plastic shells out of the way. See picture 1.
I personally didn’t have to use any kapton tape, but if you are nervous about possibly melting the plastic on the cartridge connector, protect it with kapton tape.
2. Starting with Golf, use flux to introduce new solder to the ROM chip’s pins (U1 on the PCB).
3. Remove the ROM chip, and be careful to not lift pads from the PCB. If you are using a hot air rework station, you shouldn’t need much force to pull the chip from the PCB once all the solder joints are molten. Keep applying heat evenly over the pins, and use a pair of tweezers to occasionally touch the chip and check if it’s ready to come off.
4. Clean up the solder on the pads for the chip with your soldering iron and desolder wick. Do not press down hard with the iron, and just glide the wick across. The pads should all be clean and flat. Also, clean up the flux residue with cotton swabs and isopropyl alcohol.
5. With Teleroboxer, remove the battery from it. It is much the same as a Game Boy cartridge.
6. Remove Teleroboxer’s ROM chip, repeating steps 2 and 3 as for the Golf cart.
7. Once the Teleroboxer PCB has cooled down from the hot air, repeat step 4 with it.
At this point, you should have the chips separated from the PCBs, like in picture 2.
8. Solder the Golf ROM chip into the Teleroboxer PCB. The chip has a circle indentation on the bottom left of the top side, and this matches up with the PCB pad that has an arrow pointing to it. Carefully align the chip, solder in one leg, confirm that the chip pins and PCB pads are aligned, and proceed with the rest of the pins. Flux highly recommended!
9. Ensure that there are no solder bridges (clean with desolder wick). Clean the flux residue as in step 4.
10. Install a tabbed CR1616 battery into the PCB. You can either reuse the original if it still has a charge over 3 volts, or you can buy a new one from your favorite online vendor.
See picture 3 for what I had as the finished product.
11. Optionally, you can repeat steps 8 and 9 with installing Teleroboxer’s ROM chip in the original PCB for Golf.
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