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PostPosted: Sun May 22, 2016 9:32 am 
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Joined: Sun May 22, 2016 9:29 am
Posts: 11
Hi Guys!

Im kind of new to this reproduction stuff... i have
a Dragon Quest 3 Game and wanted to make it a Dragon Warrior 3 (as my japanese is lacking)

But my PCB is a SNROM with a 256 Maskrom and DW3 is a SUROM with a 512k Maskrom.

Is there any newbie friendly tutorial on how to do this?

rgds dario


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PostPosted: Sun May 22, 2016 10:05 am 
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Joined: Tue Dec 04, 2012 3:28 pm
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Location: Canada
I believe you should be able to just run a wire from your PRG A18 line to CHR A16 on the MMC1 chip. Check the nesdev wiki for the pinout.

You'll probably also have to lift the /CE pin on the WRAM chip and tie that to GND, otherwise it'll end up being connected to the same MMC1 pin as you want to wire A18 to.


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PostPosted: Sun May 22, 2016 10:07 am 
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Joined: Sun Apr 13, 2008 11:12 am
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Location: Seattle
If you say you're a newbie, you probably weren't aware that you'd also have to change how the ROM itself is wired:
nesdevwiki:Mask ROM pinout

After the changes to the ROM, to change SNROM to SUROM you'll need to change one pin out of the MMC1, and one pin into what the PCB calls "WRAM".
nesdevwiki:MMC1 pinout


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PostPosted: Sun May 22, 2016 10:32 am 
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Joined: Sun May 22, 2016 9:29 am
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For the Rom Pinout i always use

http://jensma.de/nesrepro/

Which tells me for my SNROM 512 - 27c040 (bin made with famirom, written with tl866) i have to lift/rewire Pin 1, 2 , 24, 30 and 31

Is this right so far? (Because he has no SUROM to choose)

And then ill have to:
Pin 31 = A 18 ( The site told me to lift it and leave it floating) has to be connected to A16 on the MMC1, and Lift the /CE on the WRAM!

Thank you so far!


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PostPosted: Sun May 22, 2016 10:41 am 
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Joined: Fri Jul 04, 2014 2:34 pm
Posts: 335
Location: Germany
SNROM -> SUROM Conversion (mapper 1):
Bend up pins 1, 2, 24, 30, and 31
Solder pin 2 to hole 24 (A16)
Solder pin 24 to GND (OE)
Solder pin 30 to hole 1 (A17)
Cut track from MMC1 pin 11 to WRAM pin 20
Solder pin 31 to pin 11 of MMC1 chip (A18)
Solder pin 20 of WRAM to Ground (CE (E1) or CHR /A13)

Here you go. Done it before, works well.


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PostPosted: Sun May 22, 2016 10:58 am 
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Joined: Sun May 22, 2016 9:29 am
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Perfect!


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PostPosted: Tue May 24, 2016 2:05 am 
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Joined: Sun May 22, 2016 9:29 am
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Looks ugly - but works fine! ;)

thx again!


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PostPosted: Thu Nov 01, 2018 10:16 pm 
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Joined: Tue Feb 16, 2016 8:22 pm
Posts: 12
(Sorry for necrobumping.)

I'm actually attempting this for the first time, I've done several other MMC3 repros for myself successfully. However, this time I'm stumped.

I'm taking a HVC-SNROM-05 DQ3 board and an AM27C040-120 programmed with the DW3 PRG (originally on a NES-SUROM). Unfortunately it doesn't boot reliably, and when it does, the graphics are scrambled. I do hear music, and I am able to control the game via controller.

I've followed the post by Ice Man, as well as verified the connections here:

socket/EPROM pin 2 and MMC1 pin 3
socket/EPROM pin 31 and MMC1 pin 11
socket/EPROM pin 30 and MMC1 pin 4
socket/EPROM pin 24 and GND

I've tried two EEPROMs so far with no luck, and the chips verify after programming with my GQ-4X4.

Am I missing something obvious?

Thanks for any advice you can offer!

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