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PostPosted: Tue Oct 11, 2016 4:21 pm 

Joined: Tue Oct 11, 2016 3:57 pm
Posts: 2
Hey guys, I want to make my first reproduction cart and have some questions. I have soldering/desoldering experience, just no EPROM experience. I'm going to do Lagrange Point for Famicom. The original famicom cart is on the way. I have read in many places that I just remove the PRG chip and install the EPROM chip with the patched ROM.

Here is the bootgod:
I can use a EPROM 27C040 correct?

I also need a programmer. Is there a common cheap recommendation for this? Can I use the Willem EPROM programmer such as this one? ... 1531758605
I don't quite understand the design of the above programmer. It uses USB power or AC. Do I interface with it using USB or DB25? Do I need AC power to write to the EPROM?

I can use a tool like below to remove the iNes header and that's all I need to do to the patched English .nes ROM file? The file I write to the EPROM is a .bin file stripped of the iNes header correct?
Tool in question:


PostPosted: Wed Oct 12, 2016 6:29 pm 

Joined: Fri May 15, 2015 5:46 pm
Posts: 13
The 27C040 should be fine. I used a 27C4001 but they should be the same.

As for an eprom programmer, I have no idea what to recommend. I've heard bad things about the clone Willems on eBay, but I've also heard that they work well enough. The biggest drawback is that you have to have a parallel port on your PC to use it. The USB to parallel port adapters designed for use with printers will NOT work. You can power it with USB or AC, I don't think it matters. But make no mistake: the USB is not for data transfer, only power.

The linked tool will work fine. Get the rom, apply the patch, then run it through the utility to get your PRG (or CHR? I can't remember. Only one file will have anything, the other will be 0kb.). You can burn the .PRG directly, it's already in binary format so no need to make it a .bin.

Here's a thread here where I explained a bit about what I used: viewtopic.php?f=28&t=12811

Note that the eprom is a drop in replacement. No need to bend any pins. The best way to get the old rom out if you don't have a desoldering iron is to cut all the legs off the chip, then head the remaining pin and push it through so it falls out. It will totally ruin the chip obviously, but trying to get it out in one piece will probably ruin your board too. Then use a desoldering braid to clean up any excess solder in the holes. It's a little tricky.

I'm also open to selling my copy if you're interested. I just don't really play it that much.

PostPosted: Thu Oct 13, 2016 2:09 pm 

Joined: Tue Oct 11, 2016 3:57 pm
Posts: 2
Thank you!!

I'm definitely off of the willem programmer idea as I don't have a parallel port or a power supply for it! I'm looking at the minipro now: ... 1092473435

I've read good enough things.

PostPosted: Thu Oct 13, 2016 5:11 pm 
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Joined: Sat Feb 12, 2005 9:43 pm
Posts: 9548
Location: Rio de Janeiro - Brazil
catskull wrote:
The best way to get the old rom out if you don't have a desoldering iron is to cut all the legs off the chip, then head the remaining pin and push it through so it falls out.

Really? In my own experience, holding the board sideways and heating pins from the top while using a desoldering pump from the bottom has been far less traumatic (for me and for the PCBs than trying to use any sort of cutting tool in such a constrained space.

In the end I may have to revisit a couple of holes that still have a little solder on then, but with a little patience I more often than not end up with everything cleanly separated and in 1 piece.

PostPosted: Fri Apr 07, 2017 11:43 am 

Joined: Fri Apr 07, 2017 7:53 am
Posts: 2
Sorry if I'm reviving an old thread no one cares about - Catskull the info on your site was immensely helpful for this project.

I used a 15$ straight outta china Eprom Eraser and a 35$ from Hong Kong Minipro TL866 or whatever. Yes I waited about a Month to get all my parts...

Process started off a little funky as my only windows computer is a laptop with no CD drive, so I had to rip the files from the mini-CD on my moms computer then swap em onto a external hard-drive to install the mini-pro software onto my laptop. I used the nes mapper/reader/splitter thingy from rom-hacking, as well as Lunar IPS

Then the M27C4001 chips that I used...well I ran one for a cycle in my eprom eraser, and it didn't want to even read in the blank check. Provided I didn't have the right chip info entered in the Minipro software, and once I got the right manufacturer/chip number, I still couldn't get the dang thing to attempt to read my eprom for the blank check, it would just error I just started grabbing fresh ones as I have about 10 lying around until I found one that read and verified as blank without running it through the eprom eraser.

Once that was sorted I had to get a working rom. For whatever reason the first rom I downloaded and patched without testing in an emulator wouldn't boot past the start screen. It would load right up but for whatever reason the start key wouldn't do a darn thing. Downloaded a rom from a different source, tested before and after patching to make sure it was a good rom.

As far as the actual physical work, I've only ever Desoldered about 4 pins while AV Modding my Famicom, but I do have 2 solder suckers. One was 8$ from ebay, and the other came in a soldering kit I got for 50% off from RadioShack for a grand total of around 20$. Great soldering iron kit for that price IMO if there are any radioshacks in your neck of the woods they all seem to be running major sales as the company is again bankrupt.

ANYWAY, it was SUPER easy. These are "single sided" solder pads I believe, so the solder doesn't typically flow through and get all jammed up on the other side, its just sitting on the back side. It took maybe 5 minutes to desolder the chip and like I said, I am NOT a pro. The hardest part (always something stupid) was getting all of the legs of the EPROM to fit into the holes on the PCB where the mask rom was. That took 10 minutes! Soldering up the new chips was a 2 minute job.

I was a little alarmed with the garbled text in the save slots/name entry screen, but I see now that its a very slight glitch with the patch and likely only happened because I swapped my save battery at the same time (wasn't holding saves at all prior)

GOOD LUCK if you haven't done it already, I know this post is about 5 months old. I can't wait to do more repros/translations.

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