nesdev.org

Hi there,

This is my first post, sorry if details are lacking or too in depth!

Today I attempted to flash eeproms ( 2 x S27c256 taken from an old arcade board) with Super Mario Bros and install them in a NROM-256-04 board in preparation for flashing my own roms. But alas I couldn't even get this repro to work. I picked SMB because I know that's what the cart used to be, and wanted the easiest first test T__T

The board I used was previously used for GlitchNES roms so already had chip sockets.

I found a (E) ROM, split it using TNINES, using -s switch. This gave me a 32K PRG and 8K CHR. I flashed the PRG as 32K is the right size for 27c256, right? Then tried both quadrupling the CHR to 32K (using copy /b) and later, flashing it at just the 8K size but neither worked. (Which is correct please?!)

Basically I followed this http://callanbrown.com/index.php/basic-nes-reproduction

Eeproms blank checked okay, then after writing to them, verified correctly. I used a minipro for the writing.

When I put the cart I just get a blinking red light, flashing in time with the screen turning on and off, resetting doesn't help. When I put an unmodified copy of SMB in it runs first time, no problems.

Is there anything obvious I am doing majorly wrong?
Could someone clear up my queries about the ROM sizes please?
If there's not, am I to assume it is in fact the cartridge pcb? Is there anything in this process that can cause the blinking light except for physical fault with the connection between the board and cart?

Thank you muchly for any light you can shed !

Blinking red light always means the CICs aren't working.

lexicobob wrote:I flashed the PRG as 32K is the right size for 27c256, right?

Right.

lexicobob wrote:Then tried both quadrupling the CHR to 32K (using copy /b) and later, flashing it at just the 8K size but neither worked. (Which is correct please?!)

Quadrupling the CHR to fill the chip will work no matter how the chip is wired. Writing only 8KB to a larger chip requires the chip to be wired a particular way in order to work correctly (as far as I know, NROM boards are not wired for this to work).

lexicobob wrote:Is there anything obvious I am doing majorly wrong?

Are you putting the board in the console backwards? (This is an easy mistake to make if you didn't put it back into the plastic shell before testing.)

lexicobob wrote:Is there anything in this process that can cause the blinking light except for physical fault with the connection between the board and cart?

If the title screen shows up while it's blinking, the lockout chips have failed to communicate but your cartridge is otherwise working fine. In that case, the problem could be a poor connection, a damaged lockout chip, or a region mismatch (the lockout chips are region-specific).

lidnariq, I disabled the CIC and it WORKED! THANK YOU!!

Joe, thank you in general for answering my questions! I am now one step closer to my quest for NES homebrew! <3

UPDATE: Flashing my homebrew worked too! Thanks again x 1,000,000!

I'm interested in doing the same.

As I understand it, it would suffice to buy the kazzo: http://www.infiniteneslives.com/kazzo.php ($20,-)
And an NROM flash board ($13). This board comes with a PRG and a CHR bank as I understand it.

Right?

And then hook up the kazzo, erase the CHR and PRG bank. Flash both and you can plug it in to your NES.
And if you want to flash another ROM you can.

Am I oversimplifying this, or is this really all it takes? Especially iteratively flashing the ROM on the cartridge sounds like a great feature.

fritzvd wrote:I'm interested in doing the same.

As I understand it, it would suffice to buy the kazzo: http://www.infiniteneslives.com/kazzo.php ($20,-)
And an NROM flash board ($13). This board comes with a PRG and a CHR bank as I understand it.

Right?

And then hook up the kazzo, erase the CHR and PRG bank. Flash both and you can plug it in to your NES.
And if you want to flash another ROM you can.

Am I oversimplifying this, or is this really all it takes? Especially iteratively flashing the ROM on the cartridge sounds like a great feature.

If I were you I would start a new thread to ask about how this works specifically using Kazzo. (Which looks super cool if it works as you hope!)

I was using an eprom programmer, uv eraser and an old NES cart which I put DIL sockets in for easy reprogramming, using this tutorial http://callanbrown.com/index.php/basic-nes-reproduction

Hope you can find your answers