Help with 1chip RGB bypass board and checkerboarding

[mobiusau]

I had created a post about this issue in my N64 thread, however still having issues and cannot work it out.

I have a SFC 1chip with arthrimus's SNES RGB Bypass + Dejitter Mod connected to my LCD via a RAD2x.

I am getting checkerboarding on certain games/backgrounds.

https://imgur.com/bEFJRRg

From my googling and a twitter post by Mike, it appears the RAD2x is different from most cables as its pulling sync from PIN9 (Composite)

I have tried the following:

- ran a wire from PIN 9 to CS on the board (330ohm resistor in line), checkerboarding still present
- No wire to the CS pad on the RGB board, checkerboarding still present

Anyone able to help me?

[ApolloBoy]

- ran a wire from PIN 9 to CS on the board (330ohm resistor in line), checkerboarding still present

When you did this, did you also cut the trace for composite video going to pin 9?

[mobiusau]

- ran a wire from PIN 9 to CS on the board (330ohm resistor in line), checkerboarding still present

When you did this, did you also cut the trace for composite video going to pin 9?

No. How would i do this? My electronic skills are basic....soldering and following install instructions are my limit

I had a similar issue on the N64 and the RGB board, however that was a simple bypass as i could just isolate PIN 3 by not connecting a wire to the pad and instead running a wire from PIN 9 to CS

I was looking at the board layout and am i better off cutting PIN 3 trace on arts board and connect PIN 9 to it instead?

I don't need to sync strip anything for the RAD2x cable just give it a signal from PIN 9

[ApolloBoy]

- ran a wire from PIN 9 to CS on the board (330ohm resistor in line), checkerboarding still present

When you did this, did you also cut the trace for composite video going to pin 9?

No. How would i do this? My electronic skills are basic....soldering and following install instructions are my limit

It's simple, just carefully use a razor to physically cut across the trace going to pin 9, which will isolate the pin.

[Jon Nielsen]

If the RAD2x is getting sync from pin 9 ie. composite as you mention, it could explain the checkerboarding.

As the other poster points out you'll want to cut the trace going to pin 9 on the SNES itself, not the mod board. Keep the connection with the resistor, though. If you don't want to make a permanent change you can always desolder the components leading to pin 9 on the SNES multimeter. If you have a multimeter to check for continuity it might help you in doing this. You should be able to find schematics or pics online to help figuring out the positions.

I have a couple of SNES and N64 consoles each with RGB and/or sync mods. What I like to do is put c-sync on pin 3 and then bridge to pin 7 or 9 if I want to be able to use another type of cable. I use a resistor depending on c-sync sources and again depending on the target cable. I like to keep at least one type of video-out besides the RGB mod, and I'll sacrifice composite (pin 9) before s-video (pin 7, luma). With my first mods I cut the traces, thinking it would be easier. But with a better soldering iron I find removing components easier and cleaner

Perhaps you could post a picture of your current mod with some illustration of what you intend to do...

[mobiusau]

If the RAD2x is getting sync from pin 9 ie. composite as you mention, it could explain the checkerboarding.

As the other poster points out you'll want to cut the trace going to pin 9 on the SNES itself, not the mod board. Keep the connection with the resistor, though. If you don't want to make a permanent change you can always desolder the components leading to pin 9 on the SNES multimeter. If you have a multimeter to check for continuity it might help you in doing this. You should be able to find schematics or pics online to help figuring out the positions.

I have a couple of SNES and N64 consoles each with RGB and/or sync mods. What I like to do is put c-sync on pin 3 and then bridge to pin 7 or 9 if I want to be able to use another type of cable. I use a resistor depending on c-sync sources and again depending on the target cable. I like to keep at least one type of video-out besides the RGB mod, and I'll sacrifice composite (pin 9) before s-video (pin 7, luma). With my first mods I cut the traces, thinking it would be easier. But with a better soldering iron I find removing components easier and cleaner

Perhaps you could post a picture of your current mod with some illustration of what you intend to do...

Now this might be a dumb question, but if i remove composite from PIN 9 how will the RAD2x get sync?

I would rather not cut traces (harder to revert the mod) so i will google for what components needs to be removed to isolate PIN 9.

This is the current install as per Art's install video for a 1Chip 02

https://i.imgur.com/F1h6bbz.jpg

edit: can i just bridge PIN 9 to PIN 3?
edit 2: This was Mike's post on reddit about the sync
https://www.reddit.com/r/n64/comments/h ... csync_n64/

[Jon Nielsen]

I don't think it's a dumb question. It's my understanding that csync is usually derived from stripping the sync signal out of composite. So if you have the csync part of the DeJitter mod installed it will provide sync directly through the pin(s) you connect it to. I'm not sure what level of sync the RAD2x will accept, but I'm assuming it will be fine if connected as you describe with the resistor. FYI, since the DeJitter mod replaces the system clock, the DeJittered sync can also be derived from the composite signal without outputting csync directly to any pin. As far as I know this is only relevant if you're using the OSSC by using the PLL setting. It's described in a post in the DeJitter thread on this forum. Anyway. I also think removing the component that connects the composite signal from the SNES is the best approach in your case.

Just saw your install picture and the Reddit post. Since your mod board covers the output pins, the composite component removal on the SNES is your best choice. What Mike says about TTL sync is the reason you need the resistor. Nice thick installation cable for the clock BTW

[Jon Nielsen]

I can't see the top of the board if it's possible at all, but if you're bridging pin 3 with 9, do it with a resistor first and see if it works. And you'll probably still need to remove the composite components to remove the noise.

Edit:
OK, checked Art's webpage. Cool options on his version of this mod.

Optional logic level C-Sync output for adding dejittered S-Video and Composite video. <-- if you enable this you might not need to remove anything.
Ability to disable dejitter functionality on demand. <-- you could also try and disable this to see if it's even relevant with the RAD2x on your TV.

[mobiusau]

Bridged PIN 9 to PIN 3 via a 330ohm resistor and checkerboarding is gone.

Can't see any noise/interference, looks crystal clear.

I think i will skip removing the composite signal for the moment.

Thanks for your help

https://imgur.com/a/fooNEqm

[Jon Nielsen]

Cool, congrats! And yeah why bother if it works