SNES vertical line issue

Some of you may know about this, most of you probably don't. The issue is a vertical line that runs down the middle of the screen. This affects all SNES units to some degree. See picture (not mine):

http://www.joeredifer.com/crap/snesline.jpg

Now before you post saying "This doesn't affect MY SNES unit!" or "I have never seen this line", hold on. I once thought the same exact thing. I had never (consciously) seen it before either. Different games show it differently and different SNES units show it differently as well, but the issue is the same: a graphics abnormality in the middle of the screen. Supposedly, some people have noticed this from the beginning of the SNES era, so bad caps are not the likely culprit. There are threads on Digit Press (or is it Digital Press? Aw who cares?) and Racketboy about this.

Here are the facts:

-Some people have a brighter vertical line, as seen in the picture.
-Most people seem to have a darker vertical line (darker than the rest of the picture)
-I have a slightly discolored vertical line that I must strain my eyes to see. For example, in the Metroid picture above, my line would appear to be *slightly* yellowish, but not darker or brighter.
-It affects rf, composite, s-video and RGB connections.
-Shows in some games more than others. Games to look at are the opening of Final Fantasy III as it scrolls down, Earthbound (which everyone has) and Super Metroid. Games like Super Mario Kart do not seem to exhibit this problem.
-All models/revisions of SNES have this to some degree, including the redesigned SNES 2/SNES Mini.
-If you have trouble seeing this, lowering the brightness all the way can help reveal it.

Any idea what could be the cause of this, why some have symptoms more severe than others and why it matters on what game is running? You guys are teh smartz. Figure this out!

I have no idea, either. I have noticed that it seems to be more visible the better your hookup. I never saw it in RF, I can barely see it with composite, it's definately noticeable in S-Video and the line is nice, sharp, and annoying through the RGB transcoder.

It's not nearly as noticeable on the RGB modded SNES 2, but it's still there.

Same problem. It's been driving me CRAZY! I first noticed it while playing Actraiser actually. I replaced my TV same problem, and tried both the SNES 1 and 2 just like you did...

GohanX seems to be right though, I would notice it more the better the output was.

Very strange, this makes 2 new threads about things that had just been on my mind; was going to post for help to this myself. I too have a lighter band than the rest of the picture, though it's not by much and chiefly shows against black (then again I'm only using rf or RCA...but JR makes the svid I'd been looking forward too sound pretty dreary).
Thanks to anyone who helps from me too.

Very interesting, I have never noticed it... when I get home from work I will see if I can spot it on my units. When it also affects RGB then I can only think of one of the PPU itself having some design flaw in it... in any case I will see what my units reveal to me

Quote:

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Originally Posted by TmEE

When it also affects RGB then I can only think of one of the PPU itself having some design flaw in it...

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Or the hardware tying up both S-PPUs together. I wonder if it has anything to do with the blending hardware when blending isn't being used.

There is no analog means of mixing the outputs of 2 chips together, its all digital. one goes to other, other makes analog output. All processing is digital

I'm definitely interested in your findings, TmEE.

I have noticed this on a few SNES consoles I have worked on. Its true that it appears more prominent when using S-video and black backgrounds.
I especially notice it on the initial Nintendo title screen

Here's what I just now tried and my results:

-Turning the brightness on my TV (which actually controls the black levels) all the way up makes the bar much easier to see. Solid black screens show it the most.

-All 3 of my model 1 SNES's (1 launch unit, 1 a little later than launch and 1 far later with a revised motherboard/no cartridge lock, etc) exhibited the issue to nearly the same exact degree. Not noticeable at normal settings, but can be seen on a solid black screen with brightness cranked high.

-Switched to a different power supply (also first party Nintendo). No change in results, and least not a noticeable change, anyway. If there had been any difference, I would have said it was the power supply's doing. Unfortunately I only have 2 power supply adapters to test.

Oddly enough, I can see the line in the middle of the screen on my SNES, especially over S-video, on my televisions but not when I video capture from the same cable.

I noticed similar results. It could be that the difference in the video signal is not great enough for the capture device to recognize as it digitizes.

I never noticed it (consciously) either until Appoloboy pointed it out a while back . . . it's not bad enough to bother me in most cases though. (at least on the TVs and SNES consoles I use)

I cannot see it on any of my SFCs and SNES' on my TV, neither in composhit or RGB or any setting on TV or SNES... I really tried to but no go in any way
EDIT: Saw it on one SNES, on a pitch black image with brightness up in Mr. Nutz. Gonna try my other machines too now

On my SFC, on RGB its much less noticable and its just change in brightness, but on composhit I see slight yellowness. On my EU SNES it was just change in brightness. I can only see it on bitch black with TV brightness turned up a little, and even then its very barely noticable...
EDIT2: blah, I cannot unsee it anymore, I can only see it when image moves though

So what do you think could be causing this? Could it be a power issue somewhere? The video encoder (which the RGB does pass through)? It just seems like such an odd problem and it affects different units to different degrees which suggests either aging or other issues affects it over time. Just a guess, there.