pin 3 on the snes multi av

Started by Drakon, October 12, 2008, 03:41:53 AM

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Drakon

okay.  Everywhere I look says that pin 3 of the snes multi av port is composite sync.  Yet I wire my sync cable into it and *drum roll* nothing happens....  I wire it into pin 9 and I get sync from the composite video but it goes in and out of working.  Heck I can even get some sync from the s-video luma pin.  So is the composite sync on the multi av for the ntsc snes really weak?  Or is that pin only used on pal systems?

NFG

On a PAL system that's where you'll find 12V for SCART devices, but on NTSC it's definitely C-sync.  Unless you've got a SNESjr, which may have changed it?  There's no RGB or Svideo output in a SNESjr, so maybe they removed the sync as well (just a guess).

Drakon

#2
Quote from: Lawrence on October 12, 2008, 08:49:00 AM
On a PAL system that's where you'll find 12V for SCART devices, but on NTSC it's definitely C-sync.  Unless you've got a SNESjr, which may have changed it?  There's no RGB or Svideo output in a SNESjr, so maybe they removed the sync as well (just a guess).

no it's the model 1.  I'm fully aware that the jr doesn't do rgb and s-video.  Basically I'm trying to hook it into a rgb to s-video encoder board that's meant for jamma arcade boards.  I know the encoder board works because it works like a dream on my sega genesis.  But for some reason the sync isn't working on the snes.  If I plug the green wire into the sync pin it gets sync, but then the green colours are all messed up.  But for some reason plugging the sync wire into the sync pin doesn't work.  I read that the rgb lines need capacitors on them in the ntsc version of the system.  Could that possibly be what's messing up the sync?  I just tried wiring the encoder straight into the system without capacitors

l_oliveira

Seems like you're having problems with sync level instead of RGB level. Before adding capacitors, why not hook the board on the genesis and measure the voltage level on the sync line ?
Then hook it on the SNES and measure again. If it's too low, you might have to amplify it a little bit. If it's too high, might have to put a resitive voltage divider.  The encoder will have trouble to sync if the voltage is wrong in the sync line.

Drakon

#4
Quote from: l_oliveira on October 13, 2008, 11:33:52 PM
Seems like you're having problems with sync level instead of RGB level. Before adding capacitors, why not hook the board on the genesis and measure the voltage level on the sync line ?
Then hook it on the SNES and measure again. If it's too low, you might have to amplify it a little bit. If it's too high, might have to put a resitive voltage divider.  The encoder will have trouble to sync if the voltage is wrong in the sync line.

yeah unlike most people here I don't have capacitors/resistors/voltage measuring devices handy.  But I managed to figure out the problem.  My scart cable finally came in.  And I figured since the rgb lines have capacitors on them...maybe the sync is supposed to as well?  So I wired the sync into the red line that has a capacitor on it and presto....works like a charm.  I also noticed that the rgb lines don't lose any quality regardless if they have a capacitor or not.  So I just took one of the capacitors from one of the rgb lines and stuck it in the sync line instead and now everything is good.  And was it worth it?  Surprisingly...YES.  When I first saw s-video coming out of the snes multi av I could tell something was off.  The s-video it pumps out has weak colours that aren't vibrant at all.  So now through my external encoder it has the detail of s-video and the colour vibrancy of rgb....finally looks perfect.  I borrowed a soldering iron today.  And I wired all the ground pins of my scart cable into the ground of the snes.  I also did the same for my genesis.  Now I won't get any more weird screen effects caused by lack of ground.

*edit* To celebrate this victory I made a comparison video.  In this video I compare the output from my new external rgb to s-video encoder vs the snes internal s-video encoder.  In this video the first part is through my external rgb to s-video encoder and the second is through the internal encoder.

http://www.youtube.com/watch?v=3I7Pcj5e_Hs

Notice how through my external encoder the colours are all vibrant.  I even tried turning up the "color" value on my tv using the internal s-video from the system but nothing I did could make it look anywhere as good as through my external encoder.  And the difference is so big that you can actually see it on this blurry youtube video.

l_oliveira

I'm glad to hear you got your problem solved.

In the case of the capacitors in series with the video signal their purpose is block DC and let only the AC (signal) pass through the cable.
If a capacitor exists already into the display, image quality decreases. That's the reason why there is no capacitors inside the SNES.

Other designs do have capacitors like, for example the Sony CXA1145 (old Genesis/Mega Drive) and CXA1645 (early Playstation 1 and Saturn)

RGB32E

#6
Quote from: Drakon on October 17, 2008, 10:20:23 PM
Notice how through my external encoder the colours are all vibrant.  I even tried turning up the "color" value on my tv using the internal s-video from the system but nothing I did could make it look anywhere as good as through my external encoder.  And the difference is so big that you can actually see it on this blurry youtube video.

What "external encoder" are you using? 

From the youtube video, the second half of the video looks better.   :P  Of my two SNES systems with RGB output my older rev has darker RGB and Y/C output, whereas my newer SNES has brighter output... ???

The later model RGB outputting SNES systems have odd phase/Tint on the S-Video output.  On my newer SNES with S-Video, I have to shift the tint control on my TV towards green for colors to look right (red looks purple on default/balanced setting).

FYI. The S-Video output from a tapped Genesis 3 will give you a better picture than a Genesis 2 with a Micomsoft XMD3....  :-\

Drakon

#7
I'm using this one

http://www.arcademvs.com/ARCADE_ACESSERIOR.htm

product a-22.  For some reason they took it off of ebay.  I guess their rgb to vga adapter was more popular.  It's the cheapest rgb to s-video converter I could find and it works like a dream.  And trust me it looks way better than s-video straight from the console.  I also use the same converter on my genesis 2 with the crappy KA2195D video chip.  And even that looks perfect.  I was interested in buying a genesis 3 until I heard that some of them don't have stereo sound.  And obviously this was before I got my external encoder.  And for some reason adding/removing capacitors/resistors in the rgb lines for this encoder makes no difference.  My genesis scart cable has resistors in it.  And the picture stays the same whether I wire the system straight into the encoder or wire it through the lines with resistors.  Same thing goes with the snes going into it with or without the lines with capacitors.  Only thing that's a bit strange is the colours on the s-video out of this board a little bit TOO vibrant.  When playing my nes through composite video or using something else through s-video like a dvd player or ps2 the colours aren't nearly as overpowering as the ones coming out of my encoder.  But even though they're utlra powerful it still looks great so I don't mind.

RGB32E

#8
Ok, thanks for the response.  The main issue I've encountered (to a greater or lesser degree) with external RGB to S-Video converters is the chroma noise/oscillation.  The Genesis S-Video picture you posted seems to exhibit the oscillation (horizontally scrolling diagonal noise that is easily observed on bright colors):


And the blue bar at the top of the screen seems to be showing the artifact as well... :(  The only solution I've found to minimize this is to run the sync output from the genesis through an Extron PA250 to separate the sync and feed the syncs and RGB into a AD725 based video encoder...

So, I guess I don't understand why you believe the S-Video output from the SNES can be bested by a external encoder board (more noise, oscillation on the chroma signal)?  Like I mentioned, the tint is off on some SNES systems, and the color needs to be raised, ect...

Drakon

#9
Quote from: RGB32E on October 28, 2008, 06:24:33 AM
Ok, thanks for the response.  The main issue I've encountered (to a greater or lesser degree) with external RGB to S-Video converters is the chroma noise/oscillation.  The Genesis S-Video picture you posted seems to exhibit the oscillation (horizontally scrolling diagonal noise that is easily observed on bright colors):

And the blue bar at the top of the screen seems to be showing the artifact as well... :(  The only solution I've found to minimize this is to run the sync output from the genesis through an Extron PA250 to separate the sync and feed the syncs and RGB into a AD725 based video encoder...

So, I guess I don't understand why you believe the S-Video output from the SNES can be bested by a external encoder board (more noise, oscillation on the chroma signal)?  Like I mentioned, the tint is off on some SNES systems, and the color needs to be raised, ect...

you only get that effect when taking screenshots on my capture card.  When displayed on my crt it looks perfect.  You pretty much have to be right infront of the tv to even notice it

and...seperate the sync?  you mean seperate horizontal and vertical sync?  or do you mean seperate it from composite video?

and about the snes the tint on my system is fine.  But the colours completely need to be raised, but my external encoder does that just fine

RGB32E

Well, the chroma oscillation artifact is very noticable when connecting to CRTs... :(  Turning up color works really well with the internal s-video output...

As far as the sync processing I was mentioning, The Extron PA250 is very handy for generating new/clean/standard syncs.  The PA250 can operate with SoG, Composite sync, and separate syncs for its input and output.  I use the PA250 in the capacity of Composite Sync In -> Horizontal and Vertical Syncs out.  The AD725 can accept composite sync or separate sync input (i.e. H&V).  To use composite sync on the AD725, +5VDC must be fed to the VSYNC input pin, but since I already have a new VSYNC, why not let the AD725 take care of combining!? :)

I was mentioning this setup, as its the cleanest and most flexible (works with all systems so far) means of RGBS to S-Video conversion I've encountered.  I do not care for the chroma issues of oversaturation and noise, but the issue may appear differently if you are using pal60?  So, if it ain't broke, don't fix it...  :P

Drakon

Quote from: RGB32E on October 29, 2008, 03:03:55 AM
Well, the chroma oscillation artifact is very noticable when connecting to CRTs... :(  Turning up color works really well with the internal s-video output...

As far as the sync processing I was mentioning, The Extron PA250 is very handy for generating new/clean/standard syncs.  The PA250 can operate with SoG, Composite sync, and separate syncs for its input and output.  I use the PA250 in the capacity of Composite Sync In -> Horizontal and Vertical Syncs out.  The AD725 can accept composite sync or separate sync input (i.e. H&V).  To use composite sync on the AD725, +5VDC must be fed to the VSYNC input pin, but since I already have a new VSYNC, why not let the AD725 take care of combining!? :)

I was mentioning this setup, as its the cleanest and most flexible (works with all systems so far) means of RGBS to S-Video conversion I've encountered.  I do not care for the chroma issues of oversaturation and noise, but the issue may appear differently if you are using pal60?  So, if it ain't broke, don't fix it...  :P

thanks for all the cool info.  I'm using ntsc.  My systems output ntsc-j which is pretty much the same thing.  I fixed the oversaturation from my board by installing 3 75ohm resistors on the colour wire of the s-video cord plugged into it.  Yeah I notice that sync issue when I'm up close to the screen.  But when sitting at a normal distance you can't see it.  So I'm not gonna bother trying to clean up the sync signal.

Live_Steam_Mad

#12
Hi, I am having some related issues on my SNES with getting a decent video output.

I have an NTSC USA SNES, I don't own the PAL EURO or PAL UK or Super Famicom version. It's a late serial number later version SNES with the smaller motherboard PCB but it's NOT the model 2, so it's not the redesigned small cased one. I can't use the RF output since I am in England and my equipment has only PAL-I tuners, but then again I wouldn't want to use it's RF output anyway, I want as good video output as possible. So I started to move up in the quality stakes and get to use RGB if possible.

So next I tried Composite Video. My USA SNES's composite output is horrid, lots of nasty artefacts and noisy edges, looks nasty on my Infocus In76 projector.

Next up was S-Video from the SNES but it has horrible diagonal lines on it on areas of solid color. I think it's because of the cheap and nasty thin wired S-Video cable that I got for it. But then again the RGB output has the same problem! At least it seems so. I say this because my Infocus IN76 projector won't lock onto the SCART RGB signal coming from the SNES's multipin connector SNES to RGB SCART cable, which sucks. Also BTW my IN76 won't lock onto my PAL PS1's output via the official RGB SCART PS1 cable. But when I feed the RGB signal from my USA SNES through my Pioneer DVR-LX60D DVD / HDD, the IN76 locks on perfectly but I get the dreaded diagonal lines just like on my SVideo connection cable to my SNES.

Recently I got an RGB SCART to S video converter from JS Technologies (second hand for 3 GBP) and it works great with my Pioneer LX60 using RGB output via SCART, on both NTSC and PAL signals (i.e. 525 / 60 / 3.58MHz and 625 / 50 / 4.43MHz) but it won't lock onto the RGB signal coming from my USA SNES unless it's displaying a mostly dark picture and then I can still see the obvious horrid diagonal dither / herringbone pattern lines on some coloured text, and when the screen gets brighter it just clips straight to a white screen and it's corrupted and distorted and also BTW when used with my PAL PS1 with the official PS1 RGB SCART cable the screen wobbles on dull screens and some of the colors look bad with lines on them. Yet the output looks fine when I put the Pioneer through it, colors are solid and great, quality is great.

So looks like I am screwed with the USA SNES, I just can't seem to get rid of the diagonal lines, (and I think I'll have to try a new S-Video cable with it with better shielding) but I think the diagonal lines maybe actually being generated from inside the SNES as like I say it's just as bad via RGB (albeit going through my Pioneer which then outputs via component to my pj, or via my JS tech box to convert to S video first). It shows up so well because my pj is very sharp compared to my Sony TV.

I think there's something amiss about my USA SNES and PAL PS1's RGB outputs as my pj won't lock onto them directly. Funny though how my pj is perfectly fine with my CLD-D925 laserdisc via S-Video (looks great) or my Pioneer LX60D DVD / HDD via Component (looks fabulous) or PS3 via HDMI (looks amazing).

Also both my USA SNES and PAL PS1 work perfectly with my Sony 29" Trinitron TV model KV29K5U when both are in RGB mode. But I can still see faint diagonal lines problems with the SNES in S-Video connection, it's just my TV is incredibly blurred compared to my pj even though I have the TV on maximum sharpness, so that's why the diagonal lines don't hardly bother me at all on the TV but I mostly use my pj and they DO bother me then. I don't like to use the RGB connection to my Sony TV as in that mode you can't alter the colour saturation at all (but you can on the pj in RGB SCART mode).

According to what I read here ;- http://members.optushome.com.au/eviltim/gamescart/gamescart.htm ...it seems that the NTSC SNES has a higher voltage output than the PAL model ? and that might be what is causing my problems? (Unless you use a cable with a 220uF capacitor in each of the R, G, and B lines to remove the higher - by 1V - DC offset that the USA SNES has, the cap's filter the DC offset out as cap's will only pass AC not DC). I got my SNES RGB SCART cable from a UK seller which oddly states "[this cable works with] Super Nintendo (PAL) - [as composite, I assume] but does not work as RGB without modification. Still provides picture but not as high quality." and "[this cable works with] Super Nintendo (NTSC/USA/JAP) - works as RGB."

Wish I could get to the bottom of what the problem is with the RGB output of my USA SNES not being accepted by my RGB SCART to S-Video converter (UK made) and not being accepted by my pj. And how come the same RGB output with the same cable works passing through my Pioneer LX60 in RGB passthrough, and also works fine into my Sony TV.

OK so I got curious and pulled apart the SCART end of my SNES RGB SCART cable and it has a 220uF cap on each of the RGB lines as I expected for an NTSC USA SNES to RGB SCART cable (yes I know USA doesn't use SCART LOL).

BUT it also has a 220uF capacitor on the Composite Video line (pin 9 on the SNES multiAV to pin 20 of the SCART) which is very odd since all the web pages that I've ever seen state put 220uF caps on the RGB lines ONLY. I thought that this could be the cause of my problems ? , especially when I look at the information already in this web page above!

Seller of the cable just told me that he gets the cable wholesale, and has no idea about the cable or what I mean at all  ::)

Pin 8 of this SCART cable is wired direct to pin 3 of the multiAV of the SNES (which is Composite sync on USA SNES, +12V on PAL SNES) like as though it's supposed to be a cable for PAL (where pin 8 goes direct to pin 3 at 12V for PAL SNES but on my USA SNES pin 3 is Composite Sync instead) which is odd since it's supposed to be an NTSC SNES cable, i.e. the NTSC SNES to SCART cable is supposed to have pin 8 wired to pin 10 on the multiAV which is +5V on the USA SNES, and supposed to have pin 8 wired to pin 16 through a 180 Ohm resistor. Although the cable has actually got a resistor on pin 16 of the SCART.

Those are the only two odd things about this cable.

Also I found this cable isn't shielded at all so no wonder I see diagonal lines when it goes through my Pioneer to my pj or goes into Sony TV. Darn it I'll have to buy a new cable. But which one to choose?

I today tried bridging pin 8 of this cable's SCART (which has Composite sync from pin 3 of my USA SNES) to pin 16 (end of the 180 Ohm resistor, i.e. on the other side of the resistor from pin 16) so that pin 8 of SCART got +5V instead of (well in this case as well as LOL) Composite Sync. Made no difference. I did this with pliers live in the socket LOL. Neither did it make any difference when I bridged the red green or blue wires direct to their SCART pins bypassing the cap on each wire.

I am going to try and take all 4 caps off the cable and see what that does, if anything.

Otherwise I don't understand why my Sony TV locks onto the RGB SCART signal from my USA SNES, as does my Pioneer LX60D, but my pj and RGB to SCART converter from JS Tech do not.

If anyone has any experience or insight with the above problems then I'd love to hear it.

Sorry about the lengthy post but it's driving me mad with the diagonal lines on my SNES.

Cheers,

Alistair G.

Live_Steam_Mad

#13
Here is a picture of how bad the problem is, this is via SVideo from the USA SNES to my IN76 projector. Note the diagonal lines / herringbone / crosshatch pattern. Anyone know why I get this or how to get rid of it? When I tried my SNES RGB SCART cable (had to go through my Pioneer LX60D to get the signal to lock on) it still shows these stupid diagonal lines just the same and just as bad.

Have I got a SNES from a bad batch or something?

Cheers,

Alistair G.

imparanoic

have you tried obtaining a rare japanese rgb 21 ( looks like scart, buy wired differently) SHVC-010 ( pricey can be as high as gbp50), then feed through another rare item xrgb2/2 + ( around gbp70 to gbp130) or expensive3 (200+)

altrenative, there is a ebay seller making custom snes to jap 21 rgb leads for 13gbp

i am using a ntsc purple snes ( later large ver) with xrgb via SHVC-010 on my sony 40' bravia 3 tv, also perfect pics

but these are pricey items (however, as i am based in hk, i found these items for a fraction of the price)

xrgb is almost the holy grail to play classic games

Drakon

#15
wow I forgot I made this thread.  I fixed this problem aeons ago by adding a 220 uf 10v cap to the composite sync wire.  Diagonal lines on s-video......I think I get that but they're kinda weak so I never bothered to muck with fixing it