ReproX: my $2 DIY repro pcb for simple mapper NES games Q&A

A place that you can discuss reproduction of classic titles or "licensed-for-reproduction" homebrew for personal use.

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thezerobit
Posts: 2
Joined: Sun Dec 24, 2017 2:01 pm

Re: ReproX: my $2 DIY repro pcb for simple mapper NES games

Post by thezerobit » Sun Dec 24, 2017 2:11 pm

I'm curious if anyone has had problems (or success) getting a NES-NROM-256 game running on the ReproX board. I ordered some of the boards and EPROMs from game-tech, and I've successfully created Battletoads, and Dig Dug repros. I created a NROM test board with sockets, which I used successfully for Dig Dug. I cannot, however, get a Super Mario Bros (NROM-256) repro working. I'm trying to get a SMB hack (of my own creation as a present for my daughter) working, I even tried regular, unaltered SMB (verified that CRC32 on each ROM image matches the bootgod records) and it doesn't work. It just gives me a grey or green screen. I've doubled (quadrupled, etc) the ROM images to fit the chips. I've tried both the AM27C128 and the AM27C020 chips for the CHR. I switched the mirroring. I checked the datasheet for the AM27C020, and it allows pin 1 pulled high or low. I chose high which worked for the Battletoads repro. I've polished the pins on the old EPROMs, verified the data, tried multiple different EPROMs. I'm either really unlucky, or I am missing something.

thezerobit
Posts: 2
Joined: Sun Dec 24, 2017 2:01 pm

Re: ReproX: my $2 DIY repro pcb for simple mapper NES games

Post by thezerobit » Sun Dec 24, 2017 4:01 pm

I did some further tests and my NROM socketed test ReproX board can run Dig Dug and Championship Lode Runner, which are both NROM-128, but can't run Super Mario Bros or Chubby Cherub, which are NROM-256. This page suggests that the mirroring is different: http://wiki.nesdev.com/w/index.php/Programming_NROM and that NROM-128 games mirror at $C000 and $8000 but generally run from $C000-$FFFF range while NROM-256 run only from $8000-$FFFF. If the PCB, as configured for NROM, only maps the PRG ROM to $C000, then only NROM-128 games would work--which is what seems to be happening. Or, possibly, one of the jumpers already handles this, and I really suck at soldering.

SuperScriptKidd
Posts: 13
Joined: Mon Nov 18, 2019 7:26 am

Re: ReproX: my $2 DIY repro pcb for simple mapper NES games

Post by SuperScriptKidd » Mon Nov 18, 2019 7:38 am

thezerobit wrote:I'm curious if anyone has had problems (or success) getting a NES-NROM-256 game running on the ReproX board. I ordered some of the boards and EPROMs from game-tech, and I've successfully created Battletoads, and Dig Dug repros. I created a NROM test board with sockets, which I used successfully for Dig Dug. I cannot, however, get a Super Mario Bros (NROM-256) repro working. I'm trying to get a SMB hack (of my own creation as a present for my daughter) working, I even tried regular, unaltered SMB (verified that CRC32 on each ROM image matches the bootgod records) and it doesn't work. It just gives me a grey or green screen. I've doubled (quadrupled, etc) the ROM images to fit the chips. I've tried both the AM27C128 and the AM27C020 chips for the CHR. I switched the mirroring. I checked the datasheet for the AM27C020, and it allows pin 1 pulled high or low. I chose high which worked for the Battletoads repro. I've polished the pins on the old EPROMs, verified the data, tried multiple different EPROMs. I'm either really unlucky, or I am missing something.
I've tried to create a simple NROM from these boards with a 512 28 pin chip, the same chips that work in my NROM donor. The rom is super mario 1, NROM-256

All I get is garbled graphics.

I have 4 NES and one clone system, the NES machines are dying, red screens even after 72 pin replacement.

So instead of hitting reset and adjusting the rom I switched to all new hardware. I will post a picture of the screen graphics, and the front and back of my board. Please help, I've wasted 15 hours debugging this.
Attachments
20191118_001958.jpg
20191118_043240.jpg
20191118_043201.jpg

lidnariq
Posts: 9383
Joined: Sun Apr 13, 2008 11:12 am
Location: Seattle

Re: ReproX: my $2 DIY repro pcb for simple mapper NES games

Post by lidnariq » Mon Nov 18, 2019 11:37 am

There is, unfortunately, almost an endless number of things that could be going wrong.

However, given the specific noise pattern on screen, it does seem likely that at the very least,
1- your CHR ROM is presenting different data than what you want it to contain, and
2- your PRG ROM is at least vaguely functional, since it's turning on the display

Is this a photo of "plain" SMB, or your hack still? I don't believe I see anything in plain SMB that looks like the tiles on your screen (although last 20 tiles are candidates)

SuperScriptKidd
Posts: 13
Joined: Mon Nov 18, 2019 7:26 am

Re: ReproX: my $2 DIY repro pcb for simple mapper NES games

Post by SuperScriptKidd » Mon Nov 18, 2019 6:17 pm

lidnariq wrote:There is, unfortunately, almost an endless number of things that could be going wrong.

However, given the specific noise pattern on screen, it does seem likely that at the very least,
1- your CHR ROM is presenting different data than what you want it to contain, and
2- your PRG ROM is at least vaguely functional, since it's turning on the display

Is this a photo of "plain" SMB, or your hack still? I don't believe I see anything in plain SMB that looks like the tiles on your screen (although last 20 tiles are candidates)
**Edit: I will boot up VM and burn Ice Climber (U)(!) NROM-128 , please give me a few.

Hey!

Thank you for your knowledge. The ROM is Super Mario 1 (W)(!) It should be the best dump, unedited besides the header being removed for "nes". I was toast after many hours of trying to get this up, but perhaps today or tomorrow if I have time I can throw an NROM-128 or whatever they're called on the board.

SuperScriptKidd
Posts: 13
Joined: Mon Nov 18, 2019 7:26 am

Re: ReproX: my $2 DIY repro pcb for simple mapper NES games

Post by SuperScriptKidd » Mon Nov 18, 2019 8:57 pm

So it seems, the ReproX boards do indeed have issues with NROM-256-02 Super Mario 1 (unedited)

I had to erase some ROMS so it took me a minute but I burned NROM-128 Ice Climber and it worked okay. Pictures included.
Attachments
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20191118_185041.jpg
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20191118_185008.jpg

lidnariq
Posts: 9383
Joined: Sun Apr 13, 2008 11:12 am
Location: Seattle

Re: ReproX: my $2 DIY repro pcb for simple mapper NES games

Post by lidnariq » Mon Nov 18, 2019 9:43 pm

... I really have to wonder about the assembly guide for the ReproX. The site says:
Group A = PA14
[...]
nrom – fixed mirroring (H or V)
A 1-2
[...]
cnrom – fixed mirroring (H or V) – add 74*161 IC
A 2-3
[...]
gnrom/mhrom – fixed mirroring (H or V) – add 74*161 IC
A 2-3
[...]
unrom/uorom – fixed mirroring (H or V) – add 74*161 and 74*32 ICs
A none
... just for giggles, try resoldering A to 2-3 instead of 1-2.

SuperScriptKidd
Posts: 13
Joined: Mon Nov 18, 2019 7:26 am

Re: ReproX: my $2 DIY repro pcb for simple mapper NES games

Post by SuperScriptKidd » Tue Nov 19, 2019 5:04 pm

lidnariq wrote:... I really have to wonder about the assembly guide for the ReproX. The site says:
Group A = PA14
[...]
nrom – fixed mirroring (H or V)
A 1-2
[...]
cnrom – fixed mirroring (H or V) – add 74*161 IC
A 2-3
[...]
gnrom/mhrom – fixed mirroring (H or V) – add 74*161 IC
A 2-3
[...]
unrom/uorom – fixed mirroring (H or V) – add 74*161 and 74*32 ICs
A none
... just for giggles, try resoldering A to 2-3 instead of 1-2.
Thanks,

It will take abit because my reflow station is at the shop and I have to get it here because my programmer's software runs on XP so I gotta use a VM. But I'll give it a shot today!

SuperScriptKidd
Posts: 13
Joined: Mon Nov 18, 2019 7:26 am

Re: ReproX: my $2 DIY repro pcb for simple mapper NES games Q&A

Post by SuperScriptKidd » Fri Nov 22, 2019 1:14 pm

I tried 2-3, didn't work. I was told to make it a UHROM, I did and SMB loaded but no hacks, even the basic. This I'm sure is fault on my end. These boards are awesome so I will be ordering more.

Thank you to everyone that gave me their time!

*edit, I dont want anyone thinking this is for piracy or hacks. I was trying to make a NROM 256 board to walk through the source for SMB 1. That's the best way for me to learn.

I need to buy more ROM repro stuff from ReproX then continue to study ASM 6502.

scandy
Posts: 1
Joined: Tue Jan 07, 2020 7:32 am

Re: ReproX: my $2 DIY repro pcb for simple mapper NES games Q&A

Post by scandy » Mon Jan 13, 2020 11:15 am

Hi and happy new year! :wink:
Maybe I ask too much as "first experience" with a NES repro, but I'd like to use a ReproX board to play the Ghostbusters Remastered Hack on my console.
It should be a MHROM mapper, 32000 bytes.

May I ask for a little help to pick all the parts needed from the ReproX page please? I'm a newbie in NES repro but I have experience with Genesis repro (I have a soldering station, an EEPROM programmer etc.).

Thank you!

Ice Man
Posts: 530
Joined: Fri Jul 04, 2014 2:34 pm

Re: ReproX: my $2 DIY repro pcb for simple mapper NES games Q&A

Post by Ice Man » Mon Jan 13, 2020 11:39 am

All described on their website:
https://www.game-tech.us/use-reprox/

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