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 Post subject: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 10:47 am 


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So I had a CSYNC RGB Mod done to my Snes Jr by a trusted modder & a Coaxial SCART CSYNC cable made by the only shop in the states. The image is nice and sharp but there's a problem with the image that is literally driving me insane.

IMGUR for a quicker comparison: https://imgur.com/a/zvqOB
Google Drive for lossless originals: https://drive.google.com/open?id=0B2WY2 ... HFOVGd2TTg


I care immensely about image quality and having spent about $300 in total (snes Jr, OSSC, cap card that works and new sound cap card) to get as high quality of captures of the SNES as possible, I find this image problem maddening. I would thank you all immensely for any advise you may have as to what source of this problem may be.


Last edited by GigaBoots on Sat Oct 21, 2017 3:20 pm, edited 1 time in total.

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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 11:46 am 



Joined: 08 Mar 2017
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1Chip RGB overdrive.
This is a known problem with all 1Chip consoles.

@borti4938 has documented the known fixes. So far only the 'alternative method' with the AVcc resistor works 100%.
https://github.com/borti4938/SNES-AddOn ... README.txt

This is how it looks like (here using a 30 Ohm SMD resistor, but 20 Ohm is recommended now):
Image

Beware that the S-CPUN is rotated on the Jr, I believe.

Edit: Another picture. This is also nicely done.
Image


Last edited by rama on Sat Oct 21, 2017 12:04 pm, edited 4 times in total.

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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 11:51 am 


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rama wrote:
1Chip RGB overdrive.
This is a known problem with all 1Chip consoles.


Thank you for the quick response.

With that being so, shouldn't the modder who installed the RGB Amp have accounted for that in his mod? That seems so strange to not prevent.


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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 11:54 am 



Joined: 08 Mar 2017
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GigaBoots wrote:
rama wrote:
1Chip RGB overdrive.
This is a known problem with all 1Chip consoles.


Thank you for the quick response.

With that being so, shouldn't the modder who installed the RGB Amp have accounted for that in his mod? That seems so strange to not prevent.


It's not his fault.
Knowledge about these things spreads slowly and this mod in particular was found just about a year ago.
It's still in somewhat of a verifying stage and it'll be like that until some more respected modders agree with it.
That, or someone finds a better solution :)

There's one problem with this mod: It's pretty dangerous to do.
The pins are close together and in a cramped space. Lifting it and installing a resistor in that location requires some skill.
If people do it wrong, it will probably kill the console.


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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 12:05 pm 


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rama wrote:
There's one problem with this mod: It's pretty dangerous to do.
...
If people do it wrong, it will probably kill the console.

Well that's terrifying. I wish I had known about this before I had gotten the mod. I got the SNES Jr specifically to get this mod done. Oi vey.


Well, with that mystery solved let me ask you this in exchange for my eternal gratitude. Any idea what's up with this? Luma problems on PS2 SCART cables as shown in the link below. I have the Coaxial SCART from this shop now and they also exhibit the same level of luma problems as demonstrated in this video.

Video examples: https://www.youtube.com/watch?v=4ZzTyioIvM8

The Component Cable performs better in regard to noise and seemingly identical in regard to sharpness.


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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 12:17 pm 



Joined: 08 Mar 2017
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Oh gee, this looks more like mistimed clamping, rather than a shielding issue.
Any analog to digital conversion requires a known black point in the video waveform, known as the clamp point.
Where to look for this clamp point is a software setting in the ADC (in a Framemeister, TV, capture card, etc) and it can be slightly wrong sometimes.

Your Component cables probably work better in that regard because Component video sync timing is better specified than RGB.
Component has more issues with color mixing on the other hand.


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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 12:20 pm 


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I see. All of these clips/images were captured via an OSSC. Is the clamp point adjustable via one of the many advanced timing settings or is something just not working right?


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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 12:24 pm 



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It can probably be adjusted!
Try some other low pass filter settings for sync, or look for any clamping related settings.


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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 12:25 pm 


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Thank you, Rama. I owe you a billion.


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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 12:26 pm 



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No probs, I'll take a beer if you're around ;p


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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 12:36 pm 


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rama wrote:
There's one problem with this mod: It's pretty dangerous to do. The pins are close together and in a cramped space. Lifting it and installing a resistor in that location requires some skill.
If people do it wrong, it will probably kill the console.


I'll back this up as someone who works with surface mount electronics quite often, I strongly dislike lifting such fine pins. And if you've ever bent a paper clip repeatedly until it snaps, you have a good idea of the risks inherent in this modification. Bending metal screws with its crystalline structure, or I guess what you could call its grain, making it harder at the point of stress and less ductile. One of those animals best left alone imo... maybe the trace itself that leads to pin 155 could be interrupted/cut and rerouted instead, but I'd have to open my SNES Jr. up to see.


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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 12:46 pm 


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On my 1CHIP-03, I just did the 750 Ohm resistor mod as per RetroRGB's page on it here:

http://retrorgb.com/snes1chip.html

I also restored csync by soldering back in the missing components from a kit.

For my SNES Jr., I just installed Voultar's latest RGB bypass board. It's an easy install, and gives you the very best results.

http://voultar.com/index.php?route=product/product&product_id=51
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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 12:49 pm 



Joined: 08 Mar 2017
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Image
(Ignore the colored traces, that's a different project :p)

Pin 155 (AVcc) unfortunately isn't isolated. The same 5V plane feeds several other components.
I'm not even sure that cutting the trace leading to 155 would disconnect the entire 5V plane.
As you can see, it is via'd to the backside as well.

But I agree, lifting that pin isn't exactly good for it.
A good modder would have to carefully lift it, and solder in the resistor in such a way that it supports the structure against vibration.

@FBX:
The regular 3 line RGB resistor mod only fixes the brightness. It does little to fix the ghosting.
Then again, with the overbrightness fixed, the ghosting appears reduced and you can only spot it if you look for it.
It still shows up on a scope, of course.
Edit: This is an old capture that I did using a console modded the regular way. Color is inverted to show it better:
Image


Last edited by rama on Sat Oct 21, 2017 12:54 pm, edited 1 time in total.

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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 12:49 pm 


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FBX wrote:
For my SNES Jr., I just installed Voultar's latest RGB bypass board. It's an easy install, and gives you the very best results.

http://voultar.com/index.php?route=product/product&product_id=51

This actually is his SNES Jr. RGB mod. I got it recently, too.


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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 1:14 pm 


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GigaBoots wrote:
FBX wrote:
For my SNES Jr., I just installed Voultar's latest RGB bypass board. It's an easy install, and gives you the very best results.

http://voultar.com/index.php?route=product/product&product_id=51

This actually is his SNES Jr. RGB mod. I got it recently, too.


Then are we sure this is a brightness issue and not some sort of voltage ripple? I don't really see this problem on either of my consoles, but I can do some test screencaps to make sure. I'll use the Mega Man X game to test for that.
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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 1:34 pm 


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FBX wrote:
Then are we sure this is a brightness issue and not some sort of voltage ripple?

Is it possible for a voltage ripple to be so consistent? This aberration is constantly present.

FBX wrote:
I don't really see this problem on either of my consoles, but I can do some test screencaps to make sure. I'll use the Mega Man X game to test for that.

That would be lovely.


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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 1:35 pm 


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Okay here's a 4x scaled screencap of Mega Man X on my 1CHIP-03 (and my apologies for the compressed jpeg image, but that's the best my external capture device can do):

Spoiler: show
Image


No ghosting or banding whatsoever. That's just with the 750 Ohm resistors mod, and also the csync restoration kit.

I'll have to wait until later tonight to do screengrabs from the SNES Jr. with Voultar's board installed. My brother is currently borrowing it.
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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 1:37 pm 



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These are two separate symptoms, caused by the same design flaw in the S-CPUN.
The DAC overdrives the analog video, making it output more than 0.7V maximum per color and also creating distortions.
If you reduce the brightness, you fix that issue, but the distortions are still present.

If you could fix the design flaw, you fix both symptoms at the same time.
One such fix is the 20 Ohm current limiting resistor.

When you check your console to see if it has the distortions, please don't just take a picture of a random game.
You need to enhance the symptom to really see it.
Use the game Yoshie's Island (it draws more current from the SNES) and turn up the sharpness setting on your display.
You may want to tune the contrast setting as well.
If you jump with Yoshie, you will notice distortions in a long streak to the right of the sprite.


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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 1:41 pm 


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Well the point here is he was getting clearly visible ghost images of Mega Man's health bar. In mine, you can't see any of that at all. If you have to go to the extreme of doing negative image with oversharpening filters and enhancements, you're getting to the point where any analog artifact is going to get blown out of proportion.
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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 1:45 pm 



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FBX wrote:
Well the point here is he was getting clearly visible ghost images of Mega Man's health bar. In mine, you can't see any of that at all. If you have to go to the extreme of doing negative image with oversharpening filters and enhancements, you're getting to the point where any analog artifact is going to get blown out of proportion.


That's not quite correct.
Different video processors greatly affect how visible the distortion will be.
It might be invisible on an OSSC or Framemeister, yet clearly show up even on a regular old CRT.

That's why I mentioned looking at the scope.

Same thing with people claiming they don't get jailbars on their consoles. Their video processing chain just hides it better than others.


Last edited by rama on Sat Oct 21, 2017 1:47 pm, edited 1 time in total.

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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 1:46 pm 


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What is this 750 ohm resistor mod you speak of FBX? I had Voultar perform the mod himself so I literally know none of the specifics of this endeavor and if it implies the installation of this 750 oh resistor.

If it matters at all, I selected the option to add S-video functionality. Would that cause these problems? Also, I promise I'm not a total idiot about tech, just analog video/modding.


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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 1:52 pm 


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GigaBoots wrote:
What is this 750 ohm resistor mod you speak of FBX? I had Voultar perform the mod himself so I literally know none of the specifics of this endeavor and if it implies the installation of this 750 oh resistor.

If it matters at all, I selected the option to add S-video functionality. Would that cause these problems? Also, I promise I'm not a total idiot about tech, just analog video/modding.


The 750 Ohm resistor mod I did in my 1CHIP-03, not the junior. I had linked to RetroRGB's page on it before, but here it is again (read the section called "Brightness /' Signal correction":

http://retrorgb.com/snes1chip.html

And again, I will do more extensive testing (as well as test my modded Junior later tonight). If I don't see your ghosting (which honestly I would have OCD'ed by now if I saw that), I'm more inclined to think you've got something actually failing in your Junior, like a cap or voltage regulator.

Now I don't mean to dismiss what rama is claiming it is, but since you're having such blatant ghosting problems with your Junior that I simply haven't seen in mine with the exact same bypass board, I'm more inclined to think something else is going on here.
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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 2:10 pm 



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Image
Quote:
This is what "pure white" looks like


What did you use to capture this? Is it a pc oscilloscope?
Whenever you get that kind of ringing on a pure white screen, it will show up as distortions.


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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 2:21 pm 


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rama wrote:
Quote:
This is what "pure white" looks like


What did you use to capture this? Is it a pc oscilloscope?
Whenever you get that kind of ringing on a pure white screen, it will show up as distortions.

I captured the OSSC into a capture card that can record SNES and that's a waveform in Sony Vegas. I assure you the problem isn't the capture card, it shows up on the TV.


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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 3:03 pm 



Joined: 24 Jun 2015
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I can see the ghosting on my SNES mini, very annoying. It's noticeable on a TV screen through both an OSSC and framemeister.

I'm using an older amp board from retrorgb, but I feel like ths7374 wouldn't fix it, just make it less noticeable.


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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 3:03 pm 


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rama wrote:
Use the game Yoshie's Island...If you jump with Yoshie, you will notice distortions in a long streak to the right of the sprite.


You weren't kidding, geez that's ridiculous. Now I really need to solve this problem..

Clip: https://www.youtube.com/watch?v=3oj5M6qdvq0
I put a couple pics of this in the Google Drive folder: https://drive.google.com/open?id=0B2WY2 ... HFOVGd2TTg


Last edited by GigaBoots on Sat Oct 21, 2017 3:10 pm, edited 1 time in total.

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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 3:05 pm 



Joined: 05 Dec 2012
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GigaBoots wrote:
With that being so, shouldn't the modder who installed the RGB Amp have accounted for that in his mod? That seems so strange to not prevent.

Absolutely not.

That isn't "normal procedure" for SNES mods and people posting here need to have the courtesy to not spread misinformation. While Borti's mod seems to fix the issue, it's an invasive, irreversible mod. I appreciate people striving to squeeze the 0.001% extra quality from their consoles (after all, that's what my site is all about)...and I really, really love that people are now being cautious of all modders, but please just be careful with your recommendations. Saying that's "the fix" will result in many people killing their consoles for a solution that has very little testing, compared to the thousands of people who have done the other recommended mods. Remember, we're looking to get the best out of our consoles and preserve them!

The best way to reduce the ghosting for 99.9% of SNES enthusiasts (including me), is just by using a THS7374-based solution that's properly attenuated. Borti himself has made an excellent board for this, as well as Voultar. I have spend a ridiculous amount of time with both solutions and can vouch for their quality. Anyone that wants better quality then that should expect to pay an extremely high price for an EXPERT modder to do Borti's other mod, for a minimal quality difference. It is by no means a "standard procedure".


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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 3:14 pm 



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I've taken pictures of oscilloscope readings from my 1Chip showing a 100% white screen.
Sorry for the low quality mobile phone cam...

With 20 Ohm resistor:
Image
Without resistor:
Image

As you can see, the no resistor waveform compares well with the Vegas analysis. Also you say that you can see this on your TV.
Your SNES has a mod, which consists of a very good RGB amplifier and correct attenuation for 1Chip consoles.
Yet you still get that distortion, so there's still something wrong.

I'm no trained electrical engineer and video is a complex topic, so I might still be wrong, but my guess is that the distortion happens in the DAC itself.


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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 3:15 pm 


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retrorgb wrote:
The best way to reduce the ghosting for 99.9% of SNES enthusiasts (including me), is just by using a THS7374-based solution that's properly attenuated. Borti himself has made an excellent board for this, as well as Voultar. I have spend a ridiculous amount of time with both solutions and can vouch for their quality.

I know of their reputation. That's why I went to Voultar but everyone here seems to think this is unusual for a THS7374 mod and that's what I got from Voultar. I'm not trying to point fingers here. I just want to figure out what's happening and get it solved.
retrorgb wrote:
Anyone that wants better quality then that should expect to pay an extremely high price for an EXPERT modder to do Borti's other mod, for a minimal quality difference. It is by no means a "standard procedure".

So are you implying here that there's a higher quality mod than the one voultar provides with the THS7374 or am I misinterpreting this entirely and you didn't realize I already have Voultar's mod?


Also yes, that mod above sounded dangerous AF.
Also, hi Bob. I'm a fan of your work.


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 Post subject: Re: Video probs w/ SNES RGB (Vertical Bands, etc)
PostPosted: Sat Oct 21, 2017 3:19 pm 



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RetroRGB:
I don't mean to discredit any other mods. Especially the add-on PCBs are very well designed and they use good parts for the job.
As you say, many people are absolutely happy with their modded consoles and I believe it works well on those.

Yet it still happens regularly that someone has a modified SNES and it shows these problems.
I want to get to the underlying cause and maybe find a universal fix, so that we can improve the situation for everyone.

GigaBoots:
It's also possible that something in your video processing chain is re-generating the distortion.
All it would take was an NTSC SNES RGB cable used on a PAL SNES console.
The NTSC cable would not have the required pulldown resistors for PAL consoles, for example.


Last edited by rama on Sat Oct 21, 2017 3:24 pm, edited 1 time in total.

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