NESRGB Twin Famicom

[deltronik]

I am copy pasting this from my post in the shmups forum to see if anyone might be able to help me with what I am experiencing:

Here is a link to what I am seeing with my NESRGB Twin, OSSC, and Panasonic p50s60:

You can see the title screen looks fine, but when the demo starts the horizontal distortion starts at the top and then goes down the whole screen over a few seconds. It is most noticeable on the edges, but occurs over the whole scanline. The waves covers the full height of the screen.

I doubt it is an issue with the OSSC, as it does great with all of my other systems. So it seems likely it is some issue with the NESRGB that is more much more obvious using the OSSC vs the GBS+Gefen combo.

I was actually checking the image with my GBS+Gefen setup to verify that the Keene scart commander did not introduce any “wobble” to the video of the NESRGB for another member on this forum just the other day. I definitely did not notice anything like I am seeing now, let alone what the other user was seeing with his Keene.

Anyone have any ideas what is causing this?

Thanks!

[BuckoA51]

Hmm….it does look like it could be a sync issue.. or possibly bad scaling but I doubt it if your other systems are fine. Can you try another display too?

[deltronik]

Yeah, I’ve got a couple of cheap 720p LCDs to test and a couple of 1080p PC monitors. I’ll test them and see if it makes a difference with my Famicom. I’ll also throw up the results in the compatibility thread.

I also tried my old old IBM VGA CRT monitor via a cheap HDMI to VGA adapter but could not get any picture.

Thanks!

[BuckoA51]

Hmm that’s strange, OSSC signal shouldn’t cause an issues with HDMI to VGA adapters.

Please do let me know how you get on with the other sets, I don’t have access to a RGB modded NES so any testing/troubleshooting you can do is really welcome.

[deltronik]

I tested on my 720p panasonic tc-32LX60 and have the same horizontal sync issue only with the NESRGB.

I also tested my Emachines E211H 1080p PC monitor which shows the same issue in both x2 and x3 mode.

I tried running through the Sync Strike before the OSSC and it exhibited the same issue. I have not tried removing the Extron 128 from the chain.

I’m going to need to hook my gbs-8220 CFW Project back up and confirm that I don’t see anything similar. The NESRGB did take some different sync settings with the GBS than the rest of my 240p consoles.

[BuckoA51]

Thanks for trying that, that does at least eliminate the possibility of it being the display then.

Try the pre and post coast values too, though with NES/SNES you may find if you adjust them at all you get sync dropouts. Nevertheless it will be interesting to see if it affects the picture.

[marqs]

Do you know how sync is wired with that NESRGB mod – does it use luma or c-sync? I’ve only tested a Famicom with PlayChoice PPU that didn’t have such stability issues.

[deltronik]

Thanks for the reply Markus, BTW, this scan converter really is the bee’s knees!

The mod has c-sync run to the multi-out. But now that I think about it, I need to verify which scart cable I am using since I do have composite video sync, c-sync, and sync on luma cables, I may be using the wrong one…

I’ll do some more testing when I get back home from business later this week.

[deltronik]

I have not yet hooked my GBS+Gefen back up to confirm that the issue does not exist, but wanted to pose a few of questions…

First, anyone else out there using a NESRGB with their OSSC right now?

Second, Would scalers that use a frame buffer possibly be cleaning this up and correcting the “sync” issue before it is output to the display, where as the OSSC is just passing the existing signal and line-doubling on the fly, so these sync inconsistencies are more likely to be passed on to the OSSC?

Third, could this “ripple” or “wave” be caused by a crappy PSU. I did try a couple of Adapters with this console that gave me a lot of interference, diagonal lines, and a scrolling horizontal line? I finally settled on the AC/DC adapter I have now because it has the least amount of video interference.

Thanks! I’ll try to hook my GBS+Gefen backup up soon so I can compare.

[BuckoA51]

I’m tempted to get myself a NES RGB, purely for testing/work purposes you understand.. right now I have no access to one.

[marqs]

Firmware 0.72 might help with this so it’s worth testing out.

[deltronik]

Thanks marqs,

I tried firmware 0.72 and it does not seem to have an effect.

I have not hooked up my GB-8220 because it is a pain to get hooked up and configured correctly again, but I did try s-video into a iscan pro and I could see the same horizontal wobble that I see using RGB on the OSSC.

If anything the wobble or wave looked more “digital” when using s-video to the iscan pro to the OSSC. Like I could see that the offset was exactly one pixel and it looked more like a square wave.

So there seems to be something on the sync signal, but I don’t know where to go from here…

[marqs]

Have you tried a different power supply? Also, it might be that the electrolytic caps inside the console have dried up, resulting to voltage fluctuations that cause all kind of issues like clock jitter. To rule out all video processing issues, have you connected it directly to a CRT to see if the problem is noticeable there too?

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