Utter newb wants to make some cartridges

Utter newb wants to make some cartridges
by Glitchy Furrystuff on 2009-11-03 (#52010)

Hello world,

I've been looking all over for guides that walk through cartridge building for the NES, (NTSC Toaster is my main model) and I just can't find fully helpful guides that walk through on this stuff. I can find things that give quick rundowns, but not give recommended links or anything, this is all I know about what to do:

(1) Get an EPROM writer and empty EPROM chip (right? If so... Where?)
(2) Take a Donor Cart with the same Mapper as target game
(3) Write ROM to EPROM chip... Desolder original EPROM and do whatever with it.
(4) Solder in EPROM chip where original EPROM was...

Is this correct? Did I miss anything? And where in the interwebz world can I find an affordable EPROM writer? And is it even EPROM or is it actually EEPROM?

Thanks for the time.

by Dwedit on 2009-11-03 (#52011)

Supposedly, the pinout of a NES Cartridge's ROM pins and EPROM pins isn't the same.

by Glitchy Furrystuff on 2009-11-03 (#52012)

Dwedit wrote:
Supposedly, the pinout of a NES Cartridge's ROM pins and EPROM pins isn't the same.

Wait... WHAT?!

So then, like... I must be on the wrong track all this time? Ah jeez, how would I go about doing this then and finding these materials?

by R-T-B on 2009-11-04 (#52019)

Dwedit wrote:
Supposedly, the pinout of a NES Cartridge's ROM pins and EPROM pins isn't the same.

I keep hearing this, but it works fine for me with my NROM devcart, which is little more than a couple of ZIF sockets pin for pin wired up. So I don't think that's true.

I get my EPROMS from futurlec. Be aware they come from thailand and it takes forever to get from there, but prices are reasonable. You might also try a EEPROM, which supposedly can be electrically erased rather than requiring UV light. I can recomend a Willem programmer based on PCB 5, works well for me but unless you get a third party design it needs a parallell port.

I can also highly recomend the board from retrousb.com, it's really easy to set up and I made a UOROM cart out of it for homebrew. All the parts needed can also be found on futurlec or digikey.

What games are you looking at building carts of? I may be able to help out with supplies stateside (if your in the US that is). I have a lot of this stuff lying around and can make a deal on it.

by Memblers on 2009-11-04 (#52021)

The pinouts are the same, as long as you stay with ROM sizes below 32kB (27C256). So an NROM board or CNROM board only requires the chips to be swapped. At 128kB for example, NES ROMs are 28-pin while EPROMs are 32-pin.

See the first 3 docs here for probably all the info you'd need to rewire the larger ROMs:
http://nesdev.com/#HardwareCartridges

If you plan on doing much erasing and re-writing of the chips, I'd strongly recommend using FlashROM instead of EPROM. And if you're just gonna burn a chip once, you could get OTP EPROMs which are cheaper and non-erasable.

by Glitchy Furrystuff on 2009-11-04 (#52067)

@R-T-B
My main goal right now is to make a Mother/Earthbound Zero cartridge, And sadly I cannot spare money and I'm 14 and not allowed to give out my address, I do appreciate your offer very much though.

@Memblers
I saved the files to my folders, thanks for pointing me in that direction. So this means that 32kB files are the only amounts possible to simply swap the EPROM? Dang, so I might have more work to do... Earthbound Zero is about 512 kB, PRG is 256 kB and CHR is the other 256 kB.

Also, MMC is some kind of way to say Mapper, correct? Is it just some fancy schmansy word?

by R-T-B on 2009-11-04 (#52069)

Unfortunately, Memblers is right. You'll have to do some rewiring.

Best of luck to you though.

by tokumaru on 2009-11-04 (#52070)

At least Earthbound Zero uses a common mapper/board (TKROM), it should be easy to find a donor cart for it. The rewiring is not such a big deal, and seems to be documented already.

by Glitchy Furrystuff on 2009-11-04 (#52071)

Documented? Where? I must know! I've looked up things like "NES cartridge building" on Google but can never find a guide!

I think I found myself a correct Donor cart from a game called Shadow Gate, according to http://www.nesreproductions.com/mapper4b.html found at NES Reproductions, that list said Shadow Gate was one of the compatible Mapper-i-fied ROMs, so it SHOULD be usable.

by tokumaru on 2009-11-04 (#52073)

Glitchy Furrystuff wrote:
Documented? Where?

The link that Memblers gave you, second document in the list (called NES EPROM Conversions). It says what pins to bend and what traces to cut on various boards, including TKROM.

Quote:
I think I found myself a correct Donor cart from a game called Shadow Gate

Any game listed as TKROM in this list will do.

Quote:
compatible Mapper-i-fied ROMs

I don't know exactly what you mean by this, but the games in black are games that use TKROM boards, which is the exactly the one Mother needs, so you don't need to do anything crazy like adding batteries, adding RAM or anything complex like that, but since the original ROMs are not pin-compatible with EPROMs, you still have to rewire it as described in that document.

by Glitchy Furrystuff on 2009-11-04 (#52074)

Ah, it appears I got the right game then either way ~

I thought you meant there was a different guide from the one Memblers gave me that had pictures and everything in it, but I can use these text files, thanks to you all, if I need help again I will certainly come here ~

by R-T-B on 2009-11-04 (#52076)

No problem. Just be advised that soldering can sometimes be a tricky business involving a fair amount of burnt fingers (I learned this the hard way. )

by tokumaru on 2009-11-04 (#52083)

R-T-B wrote:
Just be advised that soldering can sometimes be a tricky business involving a fair amount of burnt fingers

I have to admit that soldering and desoldering (desoldering mainly) dev carts can be tricky, but burnt fingers is not really one of the problems I have. It only hapenned to me once in several years (I don't do soldering very often though).

My biggest problem with NES boards is that there are always some holes that I can't seem to get all the solder out of, so I always end up with 2 or 3 pins that just won't come out. But if I insist I usually succeed.

by R-T-B on 2009-11-04 (#52088)

I guess I just need to practice more.

by Banshaku on 2009-11-04 (#52090)

standard nintendo board are a pain to unsolder. Konami VRC ones were a charm.

by Glitchy Furrystuff on 2009-11-06 (#52196)

Okay, I've got something that makes me want to confirm something...

I read over this list and it doesn't say anything about chips that are MMC chips, just NROM, SNROM, UNROM, etc. Both my games, according to the list, are MMC3 which I suspect is supposed to be Mapper 4? I guess because it goes by hexidecimal on MMC numbers? Bah, I'm retarded.

Also, when replacing the chips, do I replace the CHR AND the PRG chip with one chip that contains the ROM data? Or do I not even TOUCH the CHR chip? I wonder this because the ROM is supposed to be both graphic data AND programming data, but according to what I understand, graphics are stored on the CHR chip, and PRG has the programs and functions... So yeah, how do I implement one ROM holding both graphics and programming onto two chips that play as one or the other?

by R-T-B on 2009-11-06 (#52199)

Look at the wiki here. You'll find that MMC3 is usually of type TxROM:

http://wiki.nesdev.com/w/index.php/MMC3
http://wiki.nesdev.com/w/index.php/TxROM

You'll need to replace both chips from your board with equivalent size EPROMS, and probably do a small bit of rewiring if you need to replace a DIP-28 chip (28 pins) with a DIP32 chip (32 pins). This is likely the case on the PRG chip.

You should check out this site to find the rom size of the board in question, and order both chips:

If I recall, this is the cart you are trying to remake:

http://bootgod.dyndns.org:7777/profile.php?id=3553

It's a "TKROM" and has a 256KB PRG and 128KB CHR. You'll need a to get eproms in those configurations. Try to find a donor board with DIP32 sockets so rewiring won't be neccesary, otherwise DIP28 will do but you'll need to rewire some stuff.

Also, use that site I just linked if you have any curiosities about games whatsoever, you can find equal donor carts by searching by board type with the "TKROM" as the query.

Here's a donor cart that'll do. Good luck finding it though, not sure how common it is:

http://bootgod.dyndns.org:7777/profile.php?id=186

Hope this helps.

by Glitchy Furrystuff on 2009-11-21 (#52832)

Good news everyone,

http://i50.tinypic.com/2yy5oqt.jpg

I've gotten my EPROM burner and Screwdriver that works on NES carts and I've opened the cartridge, now I just need to know a little more stuff. First, sorry about blurriness on my photo above, it's my exact cartridge. This is the donor cart, however my cartridge, unlike their shown board, has the chip above the CHR (I don't remember what it is) is by SHARP and it all says on the chip:

LH5160- 10L
SHARP JAPAN
9012 3DA

The board is NES-TKROM-01, the PRG chip is 28-Pins while CHR is 32-Pins. Will this mean that I can avoid rewiring the CHR chip? I'm pretty sure though I will certainly have to rewire the PRG chip.

Also, one last thing, the usable EPROMs for this are 27C001, 27C020, and 27C256... Right? Just want to make sure.

This is the Donor cart

This is the Final Game (Japan)

by tepples on 2009-11-21 (#52833)

LH5160-10L is Sharp's part number for an 8 KiB SRAM, analogous to the better-known JEDEC #6264.

by tokumaru on 2009-11-21 (#52835)

Glitchy Furrystuff wrote:
the PRG chip is 28-Pins while CHR is 32-Pins. Will this mean that I can avoid rewiring the CHR chip?

No, you need to rewire both. The only original chips that are directly compatible with EPROMs are the smaller ones (32KB or less).