Making repoduction NES/SNES carts?

Hey there guys,
Is anyone familiar with making reproduction NES and SNES carts? I'd like to take some Famicom/Super Famicom carts and replace the ROM on them with an English translated version so I can play games that never came out in English on original hardware. What's involved in this? I know that you need eprom chips, eprom programmers and eprom erasers. I gather the process is:
1) Stick the eprom into the eprom programmer
2) Write the ROM to the eprom programmer
3) Desolder the original eprom chip and solder in the new chip

How do you know what hardware you need? What eprom chips do you need? Do they need adaptors to make them fit? I've seen many different eprom programmers, and they all go for different prices, what's the difference between them?

 

Your step by step is about right. Really it takes quite a bit of google research before you can get going. You have to to know enough about eproms and roms to know what the basic pinouts are and what they mean.

http://wiki.xtronics.com/index.php/How_EPROMS_Work
http://nesdev.parodius.com/NES%20ROM%20Pinouts.txt
http://www.caitsith2.net/snes/flashcart/cart-chip-pinouts.html#rom
http://snesdev.romhack.de/

So for most games, the nintendo rom pinouts and eprom pinouts don't match. So for simplicity's sake, let's say that pins 17 and 18 on a rom are backwards on the eprom and that all other pins are the same. The instructions would be more like:
Unsolder the rom and program the eprom.
Bend pins 17 and 18 on the eprom so the point straight out. Get two wires.
Solder one end of wire 1 to eprom pin 17 and the other end of wire one to hole 18 (or another place on the board that would be the same as hole 18).
Solder one end of wire 2 to eprom pin 18 and the other end of the wire to hole 17.
The solder the rest of the eprom to the board.

Some people prefer to bend up pins as I talked about and some prefer to cut traces and then use wires to rewire the circuit board (then they just solder in the eprom as normal)

So it's really not hard, but it does take some research and learning to get it done. Also, it can be frustrating if something seems right but then doesn't work. You definately will want to start with games that you've seen reproductions for since the translations definately work on hardware. Also start out with something easy like dragon quest V.

As far as eproms go, you need eproms that are the closest size and pinout of the roms. If it's a nes game with 28 pins, it would be nice to find a 28 pin eprom of a similar size.

As far as adapters to make them fit, you don't need adapters to make eproms fit in most games--but some games would require more eproms than would fit in a standard cartridge.

As far as which eprom programmer--I dunno. Many cheap ones are from china with who knows how much support. Many professional ones are super expensive. I have an older professional grade one that I got off ebay pretty cheap and a $100 one I got off ebay from MCUmall in canada because they seem to support them pretty well. Both have worked just as well as each other from what I've used them for.

I'm not around here too much, so don't expect me to answer further questions...

 

Thanks for that! Hmmmm, it seems quite complex! Is there a "neater" way of soldering the new ROM to the board that doesn't involve having to run wires everywhere?

 

No. Nintendo designed their PCBs with the MaskROM pinouts modified for whatever reason, perhaps to simplify PCB layout. As such, you cannot get any standard programmable part to replace the MaskROMs in most cartridges. I hear the 32 kilobyte chips are compatible with EPROMs but that is about it.

Unless you manufacture your own PCB, you will have to either cut pcb traces and run wires, or bend eprom pins up and run wires around. If done right I suppose cutting traces might *look* better. However bear in mind it's unlikely the cartridge will be opened many times afterward so no one is going to see it anyway. The only reasons to open a cartridge are, check authenticity, clean or repair, and changing batteries. You won't have to do any of those very often at all.

I highly recommend buying a flash cartridge instead. EverDrive is nice and you will spend less money playing all the games you want. Even if you just want to build games for a "collection", I would suggest buying the Tototek SuperFlash 64M instead. Just program the game you want on there as a single game, and put it in a cartridge with a nice label. The quality of such would be better than anything you put together yourself. And it saves you any soldering and wiring.

 

Wiring is as neat as it gets.

 

I see, well that's not so bad I guess.

I notice that some games require multiple eproms to be soldered together, is there a way to avoid this and only use 1 eprom (by say, using one with a higher capacity?)? Again, this is really messy looking, and it bothers me For example, what's going on here with this repo:

This looks tidier than many repos I've seen.

 

Thats how I do mine.

Its a PCB to convert tsop40 to dip. Therefore all the traces/pins are in the correct order.

 

Tell me more! Is this process radically different from running a bunch of wires to an eprom? Is it more expensive? Does it require different hardware? Is the quality/performance the same? Are the parts harder to find?

 

The soldering is more difficult - you have to solder the tsop40 chip to the pcb. You then solder the pcb into the cart, its a direct replacement in pinout etc - so there is no wires.

But unless you have experience, you will probably struggle with the soldering the chip to the pcb.

Its a little more expensive if its a low size game (as the chip is 4MB and more expensive). However, for larger games - its cheaper as you only need 1 chip.

 

"solder the tsop40 chip to the pcb"... You mean that tiny little chip in the middle of the board? You have to solder that itty-bitty thing to the board? I thought for sure it would just be a matter of soldering the board to the cartridge board! What would be the best way to do this? THIS WAY or THIS WAY?

With regards to smaller games being more expensive, couldn't you just stick the game on a larger chip and leave some free space?

 

Yes, you could stick the smaller games on it and leave the free space. But a smaller chip will cost you less - hence this method costing more for smaller games. Larger games need multiple eproms and this method chip is 4x larger (so 1 chip, rather than 4).

And yes, that little chip in the middle

Method I use is:

http://www.youtube.com/watch?v=YzI31gfCjJE

Or you could buy the board + chip preprogrammed from someone like me, then you just need to solder the board into the cart where the original chip was.
However, you need to make sure your donor cart is a match for the game you are putting on the eeprom.

 

Ah, so you're saying this method is good for large games? So for a smaller game, you can get away with using a single eprom with one or two wires? Basically, I'm interested in whatever method is the neatest and doesn't result in a rat's nest of wires running everywhere with multiple eproms flopping around the joint

Ah, the drag method is a good one is it? I'm thinking it might be fun to try and make one myself, though where would I get the parts from? Either way, I'll fire off a PM to you for the details on getting you to make a read-to-install solution As to doner carts, I'd be using the Super Famicom version of the game, that way it's compatible, and I get the original label artwork too!

Just out of curiosity, are these little chips still eproms or are they something else? If they are, do the last just as long as an eprom?

 

EPROM = programmable, but to erase you need to use UV. If the chip doesnt have a window its a OTP EPROM (one time programmable).

EEPROM = programmable, but you can erase electrically - which is why it has more pins.

The little chip is a EEPROM


Smaller games, I would use a single eprom - its cheaper and the chip should fit in the old space. You will just need to lift a couple of legs and wire them to the correct spot for the ones that dont match.

 

Do all types of ROMs last the same length of time? I'd hate to use one type only to find it suffers from bit rot well before another type!

Yeah, I had figured that you would be able to use a single eprom for smaller games. A saw a single eprom repo that only used a single wire, is this true of all single eprom repos? And are the legs you need to wire up consistent, or do they very depending on various factors? Do you need a different programmer to program these small eproms or do they work in a regular programmer (after soldering them to the board I'm assuming)?

Oh, and would you be okay with telling me what parts I would need to make a larger reproduction (i.e English-patched Seiken Densetsu 3) cart? I know that this is something you also do, but I wouldn't mind making one myself

*EDIT* Am I crazy, or is THIS WEBSITE selling the eprom chip pre-soldered to to the TSOP adaptor? That would be very convenient if they are!

 

Looks like it, but you'd still have to program it. I'd also imagine you'd still need to rewire it to get it functional.

 

have you done starfox2 / seiken densetsu 3 using those methods?

 

That website has a programming service, so they would be able to program it for me As I understand it, that adaptor matches the pins on SNES carts perfectly and doesn't need extra wires, unless I'm looking at the wrong adaptor. Can someone confirm?

 

A20 and A21 are swapped if memory serves.

 

You mean that even with an adaptor, the pins still don't line up correctly?

 

You say "an adapter" like they are all the same.

You can make an adapter that wires any pin to any other pin.