List of things you will need:
A SuperFX game with 512k of SRAM.  Stunt Race FX, Dirt Trax FX and Doom are the only games in North America that comes with 512k stock, others you will have to upgrade the RAM.  Tutorial Here
An 8mbit EPROM, I used a 27C801
Soldering tools
Lots of wire

I am using a copy of Stunt Race FX, it has 512k SRAM and has a battery to save high scores


Start off by opening up the cart


Here we can get a look at the back of the cart


And here is the front of the board, the chip outlined in red is the mask ROM, this is the chip we will be working with.
Blue is the FX chip itself and Black is the SRAM


And a close up shot of the mask ROM, we need to start by removing this chip.  There are a few different ways to go about this, hot air, heat a pin and lift it out, the hot wire method.
I will be cutting off the original mask ROM with an xacto knife


With the cart edge connector away from you drag your knife to the right towards the ground plane, this way if you pull the blade too far you only scratch the ground plane and not the small data lines on the other side of the chip.


Cut most of the legs but leave a few intact then cut them from the other direction




Once all the legs are cut you can lift the chip


Then bend the chip back and forth to snap off the legs on the other side of the chip


Now the mask ROM is removed and but the legs are still attached to the pads


Now use your soldering iron to clean the pads up, you can swipe your iron towards the middle of where the ROM was to remove the legs from the pad then use solder wick to remove all the extra solder from the pad


Next tin all the solder pads and remove the battery for now, this will make it easier to run the wires to the pads




Time to prep the EPROM, to start you need to remove the header from the ROM and swap bin the ROM before programming the EPROM.  Games using the FX chip use the same pinout as normal SNES games so you will need to swap pins 31 and 24.


Next straighten out all the legs on the EPROM


Next cut the skinny part of the legs off


Now flip the EPROM over and tin all the legs


Now glue the EPROM onto the back of the board so that the legs of the EPROM are flush with the edge of the board, face pin 1 towards the battery






Then do a test fit to make sure the cart will close once the EPROM is fitted in place


Now it is time to start wiring the EPROM to the board, I like to solder the first 10 pad then solder the battery back in place




Here is the first half of the EPROM wired to the board
The OE and CE line are connected to ground on the board so I just solder them to any ground pad that I find easy to solder to
The red wire is the swapped pin, it runs from pin 31 on the EPROM to pad 24 on the game board




And the second half of the EPROM wired, the second half does not require swapping any lines, they just get wired directly to the corresponding point between the EPROM and the game board




Now place the board back into the shell and give it a test run

Such an amazing tutorial, wish there were more like these over the Internet.
Your such a great ressource for all of us.
Thanks for sharing your knowledge.

Yeah, thank you so much for this man, I appreciate it a lot. Keep them coming

That was awesome.

That was incredible. I've never seen a more clear and thorough repro tutorial. I think a lot of people don't want this kind of knowledge leaking out to the general public? Well, thanks for sharing. I will definitely be giving this a shot... that is, once I find a second copy of Stunt Race FX (because I really like that game, lol).

Double post...

So does the SRAM battery only serve to save high scores in SF2 and will it function OK without it?

http://www.elotrolado.net/hilo_tu...

Cirellio there are tons of tutorials on the Internet...

And yes the only feature with battery is save your scores.

The game will work without the battery, it just will not save the high scores.  Star Fox 2 does not save game progress just the high scores so even without the battery you're not missing out on much.

Thanks for the info.

I had someone make me a StarFox 2 cart many years ago, but they never said anything about the SRAM being functional.
Is there a way to tell from the pics I have here: http://videogameobsession.com/vid... ?

I love the characters in SF2 also.

Nintendo really should make it available on the Virtual Console. It seems like such a waste to keep a 99% completed game hidden away.
 

The Super FX chip uses the SRAM as work RAM also, the game will not load without it.  SRAM is volitile memory and becomes blank if there is no power to the chip.  The battery will keep power going to the SRAM so it does not lose the data on the chip.

Your copy looks like it was built on a Stunt Race FX board so as long as your battery is good it should save your scores.

I totally agree about putting Star Fox 2 on the VC but you never know maybe the source was lost.

BTW did Drakon make that game for you?  It looks like there is more hot glue than wires in there.

Would be nice to see someone show the way to overclock it! I have seen some overclocked versions. Game runs smoother.

I have seen videos of over clocked FX games also, to me they do not appear to be running smoother but the game actually plays faster giving the illusion that it is smoother.

The original source code(s) were leaked in 1999 so they are definitely still around. Nintendo still has ties with key members of Argonaut, namely Dylan Cuthbert, who now heads up Q-Games. The same Q-Games who remastered StarFox 64 3D on the 3DS. It's kind of cool if you think about it all.

I'd love to see a StarFox Classics Collection show up on either the 3DS or Wii U. It could be an eShop title with StarFox 1 & 2 remastered to run at 60fps ad 3D on the 3DS. I think flat colored polygons look awesome in 3D.

It wasn't Drakon. I don't believe he's on NA. I'm OK with hot glue as long as all of the solder joints are done right and there's not need to remove anything.

I also agree about some of the overclocked FX games I've seen. They look to be running faster, but not exactly at a smoother frame rate. It must make the game more difficult.

Thank you, but I have watched other tutorials. This doesn't change the fact that I believe this is one of the clearest and easiest to follow.

OP, thanks so much for this tut. This is one I really want to play and have a cart of, and building things myself means so much more to me than paying a bunch of money for it. Plus I hope that I can build a couple more games down the line to really enjoy. Thanks again.

Finally got the courage up to try this and it worked! Thanks for the tutorial. Don't know that i want to ever make it again though geez... it was a huge pain!

Haha yea they are a pain to make, now you know why repro makers charge so much for this one.

Glad you got it working and that the tutorial helped.

added to favs...but how do you get the rom onto the chip?

Need an EEPROM programmer, most people start out with a willem gq-4x, it works OK I have a Xeltek programmer in the mail, I hope it works better.

Thanks so much for showing ''Secrets'' with us

This looks way easy
might give it a go if i can get 2x stunt fx cause i dont actually own it.

Hi
Very nice tut. Im curious with the pinout. Which line in the m27c801 is CE and oe? Im New to all this stuff. And to which point do you Solder the single yellow cable (which is not ging to the mask Rom). Can someone provide an picture with nummbers on the Pins? Like the pics you see when installing an modchip. Soldering is no Problem.would it be possible to do an starfox competition with this?

Really hope someone can help me. Sorry for Bad language... Im from germany

Cya

Here is an image showing the pinout of a SNES mask ROM on the left and a 27C801 EPROM on the right


When you swap bin the ROM using SNES ROM Utility you only need to rewire pins 31 and 24 instead of all 5, it moves the game data around so even though it is reading from the wrong pin the SNES still gets the right data.

That single yellow cable is a ground wire, I just soldered it to the crystal to make it shorter.  Any ground spot on the board will work.

Hi
Thanks for the quick answer. I am going to
Solder an zif socket on this cart just for testing. A lot of things to do in real life so this can take a while. The overclock is already soldered. Anyone got an idea in how to get this running on the Drakon speeds?
He postet everywhere that he has getting it up to 50mhz but never stated in how to do this. Just that he edited the Rom file.
So anyone can help with this?

Cya

Do not bother with an overclock, the game plays faster not smoother.