NESRGB Discoloration Issue

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santiac89
Posts: 3
Joined: Sat Apr 20, 2024 10:41 am

NESRGB Discoloration Issue

Post by santiac89 »

I'm new here so first, hi to everyone! I'm having an strange issue with my NESRGB installation that I cannot solve. I contacted Tim about it but had no response yet so also trying here.

I have a PAL NES which I modified to NTSC using PPU, CPU and Clock from a Famicom, and on top of that I installed NESRGB. The issue I'm having is specially noticeable with SMB3. Basically, there is discoloration between some screens, for example during intro colors look good, but as soon as I get the title screen the colors get dimmed. I'm posting some videos to show the issue and explain the config in each. NESRGB config is set for NTSC, De-Jitter and also J8 closed which is composite sync with 75ohm.

Here you can see the issue really clear: https://www.youtube.com/shorts/Np0iZzT2Qx8

And here is a comparision between RGB and composite, what I found weird also in this case is that from what I read composite should be showing black and white spirtes/background when using NESRGB but here I can clearly see the whole picture. I'm using the console composite directly btw, maybe that is why it does not? Anyways, first screen is using composite, look how dimmed it looks when I change the TV to RGB: https://www.youtube.com/watch?v=KE1wHsoFntM

Also, something strange I saw is that, when I plug the composite cable on my TV the discoloration gets worse on the RGB side. Not sure if related.

Here is a picture of the NESRGB board (Took it before J8 was closed btw): Image

I've tried everything but couldn't find a solution yet, best case I have is disabling de-jittering which makes it a bit better but issue still persists. Hope someone can give some light on this.

Thanks!
Last edited by santiac89 on Sun Apr 21, 2024 9:44 am, edited 1 time in total.
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Guspaz
Posts: 3147
Joined: Tue Oct 06, 2015 7:37 pm
Location: Montréal, Canada

Re: NESRGB Discoloration Issue

Post by Guspaz »

You sure the NES itself is OK? That cap next to the PPU look like it's leaking.
santiac89
Posts: 3
Joined: Sat Apr 20, 2024 10:41 am

Re: NESRGB Discoloration Issue

Post by santiac89 »

It is ok as shown in the video where the composite video is output. That mark is just paint.
santiac89
Posts: 3
Joined: Sat Apr 20, 2024 10:41 am

Re: NESRGB Discoloration Issue

Post by santiac89 »

I edited the post since the second video was wrong
Odyssey113
Posts: 10
Joined: Wed Jun 29, 2022 4:15 pm

Re: NESRGB Discoloration Issue

Post by Odyssey113 »

santiac89 wrote: Sat Apr 20, 2024 10:43 am I'm new here so first, hi to everyone! I'm having an strange issue with my NESRGB installation that I cannot solve. I contacted Tim about it but had no response yet so also trying here.

I have a PAL NES which I modified to NTSC using PPU, CPU and Clock from a Famicom, and on top of that I installed NESRGB. The issue I'm having is specially noticeable with SMB3. Basically, there is discoloration between some screens, for example during intro colors look good, but as soon as I get the title screen the colors get dimmed. I'm posting some videos to show the issue and explain the config in each. NESRGB config is set for NTSC, De-Jitter and also J8 closed which is composite sync with 75ohm.

Here you can see the issue really clear: https://www.youtube.com/shorts/Np0iZzT2Qx8

And here is a comparision between RGB and composite, what I found weird also in this case is that from what I read composite should be showing black and white spirtes/background when using NESRGB but here I can clearly see the whole picture. I'm using the console composite directly btw, maybe that is why it does not? Anyways, first screen is using composite, look how dimmed it looks when I change the TV to RGB: https://www.youtube.com/watch?v=KE1wHsoFntM

Also, something strange I saw is that, when I plug the composite cable on my TV the discoloration gets worse on the RGB side. Not sure if related.

Here is a picture of the NESRGB board (Took it before J8 was closed btw):

I've tried everything but couldn't find a solution yet, best case I have is disabling de-jittering which makes it a bit better but issue still persists. Hope someone can give some light on this.

Thanks!
Have you tried it with J8 open by chance? I'm wondering if your scart lead already has 75 ohm termination built into it, which would make sense why picture is coming out too dim...

What kind of scart cable are you using exactly?

On another note, i'm confused as to why you'd be closing J5 when your console clearly says PAL in the picture. Looks like you have a PAL console, not NTSC.
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