Another annoying Noob! Nrom question

[pinge80]

Hi! I´m the new idiot that will terrorise you with "stupid" questions! I just got what I think I´ll need to make som repros with donor boards.. my first exercise was to get Super Mario Cluds to run.. no problems so far..
and then a hacked SMB rom with swedish text.. still no problems!

And I simply wonder if it´s possible to put any NROM game on the SMB-board... will for exampele Mario Bros work if I put PRG and CHR on the board...

hanx for your time!

[tepples]

will for exampele Mario Bros work if I put PRG and CHR on the board

Yes. But Mario Bros., specifically, has a 16 KiB PRG, so you'll have to make the EPROM ignore the A14 signal from the NES. There are three ways to do this: use a smaller EPROM, write two copies of the PRG to the EPROM, or bend up the pin for A14 and ground it.

[Memblers]

You could also try CNROM, it uses 32kB for both PRG and CHR. That would allow it to run a lot of stuff, including NROM (if you duplicate the memory to fill the ROM out, like tepples said).

[pinge80]

Hey again!
I have now experimented alot with nrom boards.. all from different SMB carts, the thing is that I can change the PRG chip to one other SMB, I have tried Mario Clouds, SMB frustration and so on without any problems!

But everytime I de-solder the CHR chip and replace it with an eprom I get glitches,,, 9times out of 10 its vertical "stripes" across the screen,...

what Am I doing wrong time after time??!

please help me out.. Im running out of boards,,, and is it possible to desolder the eproms and fix the problem?!

And f.y.i i have tried different eproms and I have tried with and without sockets!

[tepples]

Vertical stripes from a CHR EPROM means that one of the data pins isn't making good contact.

[pinge80]

Still have problems with the graphics,
Are you sure it´s bacause of bad soldering? I used

I have tried the following eproms (both as PRG and CHR):
NMC27c256
TMSc256
AT29c256

But now to todays question...

When I was following the Mario-Clouds tutorial I read that you are not supposed to use Nes-Nrom-256-06

Why is that? Is it possible to use the -06 for a Smb hack? (only change PRG)..

And is it possible to make a NTSC rom to PAL?

[nintendo2600]

Still have problems with the graphics,
Are you sure it´s bacause of bad soldering? I used

I have tried the following eproms (both as PRG and CHR):
NMC27c256
TMSc256
AT29c256

But now to todays question...

When I was following the Mario-Clouds tutorial I read that you are not supposed to use Nes-Nrom-256-06

Why is that? Is it possible to use the -06 for a Smb hack? (only change PRG)..

And is it possible to make a NTSC rom to PAL?

You can convert NROM 256 to NROM 128 and visa versa. by following or reversing the following diagram:

http://8bitcollective.com/forums/viewtopic.php?id=14319

[tokumaru]

You can convert NROM 256 to NROM 128

Honestly, it's way easier to double up your ROM than do anything hardware-wise.

[pinge80]

Is there any reason at all to convert a board to 128 instead of 256? I just dont get it

[tepples]

Is there any reason at all to convert a board to 128 instead of 256? I just dont get it

From the forum post:

Ever find it to be a pain in the ass to find the NROM-256 carts?
But have a bucket full of NROM-128's?

I take this to imply that there are more dirt cheap NROM-128 games in circulation than NROM-256. The common NROM-256 games like SMB1 tend to have a higher resale value.