SNES SCART RGB just sound no picture

I just received a scart cable off ebay that was said to work with NTSC SNES. I plugged it in and only get sound....no picture. Weird. I get a pic through my N64 but weird colors....probaly my fault though. I need to look at my rgb mod again. My scart to YUV converter is not the problem either because it works great with my Saturn. AV cable work fine on the SNES and even plugging the green end while the scart is in the SNES brings a picture(although washed out) when plugged into av. I checked the capacitors on the scart cable and they were labeled 100 so I replaced them with 220. Same problem. I have not found much online for this specific problem and the forums that did discuss it had no solution. Anyone come across this before? Maybe bad scart cable?

 

When you say NTSC SNES, I assume you mean NTSC-U, right? I have a Super Famicom and 2 SCART cables for it. One of them works and the other one has weird colors. They both have an issue where the video interferes with the sound and vice versa.

 

Yeah, NTSC -U. I have also not modified the SNES in any way and have cleaned the connections in the AV port.

 

Maybe it's just a standard Gamecube RGB SCART cable being marketed as one compatible with the NTSC SNES. In theory it will work, but there won't be a switching voltage as the NTSC SNES has slightly different wiring on the Multi-Out.

Naturally, on SCART equipped TV's all that would be required is to manually switch over to the SCART input. With any sort of converter it may be waiting for a switching voltage, so maybe that's where the problem lies.

 

That sounds very likely. The plastic bag the scart cable came in was labeled "GC Scart" which I am assuming means it is Gamecube scart cable. I did not know there was a difference with the cables though....in that case I will see if there is a way to convert it to snes scart.

So I was looking at this...

http://www.mmmonkey.co.uk/console/nintendo/rgbntsc.htm

Specifically this part:
"
Also, I dont know if this is worth mentioning or if it will cause more confusion, but the official PAL GameCube Scart cable has a 75ohm resistor to ground and 220uF capacitor in series on the Composite video line - these are needed for PAL consoles but not NTSC consoles. Usually these two components dont cause any problems when using on an NTSC SNES/N64 console, but on one of my TV's they did cause the picture to 'jump' every so often, because RGB Scart gets the Sync signal from Composite video. You can remove/bypass these two components but the 75ohm resistor is a pain to remove as its hidden in the other end of the Scart cable!"

Maybe if I remove the resistor and capacitors it will work?

 

Which model SNES are you using? The smaller SNS-101 model does not output RGB as standard.

 

All it needs is a voltage above 9v on SCART pin 8, although the diagrams >>here<< shows that the +5v from the NTSC SNES will suffice.

Try running a jumper wire from Pin 8 to Pin 16. Make sure you connect it before the resistor (if present), as the voltage will not be sufficient otherwise. Also cut the connection for Pin 8, otherwise you'll send +5v back down to the SNES!

The 220uf capacitors are required for the NTSC SNES. Do not remove them as they strip out some additional voltage on the RGB and Composite lines.

*EDIT* And what link83 said.

 

Standard model 1 (not jr).

I will give it a shot tonight when I get home. That makes sense too because I get a signal fromthe N64 (which uses 12v) but not the SNES

Thanks

 

There is no N64 model that has a +12V output from the 'MULTI OUT' port as standard. Also, almost all third party SCART cables I have seen only use the +5V line, with a resistor connecting pins 8 and 16 - this ensures compatability with both NTSC and PAL consoles, and any consoles that dont output +12V like the N64.

I would recommend checking for any components on the SCART cables Composite video line, as there shouldn't be any for an NTSC Nintendo console (btw it was me you quoted in your previous post)

 

Hmm, I thought I had read somewhere that the n64 does 12v out but i trust you more because of what I have seen in your posts regarding the n64. There are no components on the composite line in the scart cable, just a direct line. Sorry if I didn't notice that it was you from the earlier post. I am using my phone for posting ATM.

 

Hmm, a few thoughts:-
- Is the cable definitely using the Composite video output from the MULTI OUT port and not C-Sync?
- Are SCART pins 8 and 16 linked with a resistor, and if so which pin is the wire directly connected to?
- Are the capacitors observing the correct polarity? (positive leg towards console, negative leg towards TV/Display)

If all the above seem correct i'm not sure what else to suggest. Can you take pictures inside the SCART plug?

 

I have no clue if it using c-Sync or composite. Not sure how to tell but will let you know when I understand how tofind out.

Pins 8 and 16 are linked with a resistor. It currently has some rubber shrink-shield on it and I will have to remove it to find out. Will let you know.

The capacitors are correct.

When I get a moment I will upload some pics.

 

Here is the pic.

Ok, I don't know how to resistor bands but they are violet, green, black, gold.

For giggles I removed the resistor and added a jumper from 16 to 8.No change.

 

Well the +5V signal (purple wire) should really be going to Pin 8, not Pin 16, keeping the resistor in place. You can fix this by following the guide here:-
http://www.mmmonkey.co.uk/console/other/rgbswitch.htm
However, since you say you already removed the resistor and added a jumper wire with no effect this might not make any difference (btw based on your color code its a 75 ohm resistor, usually a 100-180 ohm resistor is recommended but 75 ohm should be ok)

I can't make out whats going on with the Red, Green and Blue wires - the capacitors look right but I cant see where the RGB wires connect to them, and there appears to be some white insulation/tape around some? (No need to remove it, just would be good to check they are properly connected)

Also, its probably unimportant but the Composite video solder connection doesnt look too good in the photo, so you might want to resolder that, and I cant make out whats going on with Pins 1 and 2 - there shouldnt be any connection to Pin 1 if thats the case.

Apart from the above minor points it looks fine, although I would recommend checking the pinout of the MULTI OUT plug matches the SCART pinout using a multimeter:-
http://gamesx.com/wiki/doku.php?id=av:nintendomultiav
http://pinouts.ws/scart-pinout.html

You could also try moving the ground connection (red wire) from Pin 18 to Pin 17 which would match the official Nintendo cables ground pin. Although all the ground connections are usually wired up together inside a TV, I dont know if your YUV convertor is using all the available ground pins.

Other than that the above I have no idea what could be wrong, but I would try and test it using another SNES if available, and possibly another brand/type of YUV convertor just to rule that out as well. Good luck :thumbsup:

 

Your shorting pins 8 and 16 "for giggles" makes me worry. Do you understand the reason the resistor is there?

As link83 says, the 5V should be going to pin 8, although that might put the TV in 16:9 mode. If that's the case, it would need 9.5-12V for 4:3.

Pin 16 needs 1-3V for RGB mode. If you put 5V to it, it could well confuse the television.

The first step in fixing SCART issues, other than checking the wiring is correct, is to measure the voltages and check they're to SCART specification.

 

Unfortunately the NTSC SNES does not provide +12V on the MULTI OUT port like the PAL SNES, instead it has C-Sync. For SCART switching the best you can do (Without some sort of charge pump circuit) is to make it switch to 16:9 Widescreen using +5V.

 

I thought the resistor was there for PAL consoles...Eh, "shorting" you say? Will not be trying that again. Ok, so I will send the 5v to pin 8 then out to the resistor, then that to 16 pin. Is there a certain way to reconnect the resistor? Then I will move the ground connection and see what happens.

The RGB are connected to the correct pins(at least going from all the diagrams I have seen) I put the tape there to cover the connectionbetween the capacitor and the wire.

Many thanks for the help... Is there a reason I get picture from the N64 but not the SNES?

 

That particular resistor isn't just for PAL consoles, its important for any Nintendo console to SCART connection.

The resistor can be connected either way round (Resistors have no correct orientation/polarity) You just need to make sure the resistor is still joining Pins 8 and 16 like the picture, and you might want to insulate it again to make sure it doesn't short out on any other wires. You could also swap it for a 100-180 ohm resistor if you have one available. Next unsolder the purple wire from Pin 16 and resolder it to Pin 8 instead (Alternatively you can swap the wire first then solder in the resistor - whichever order is easiest) The ground connection pin swap may not help at all - I just thought it wont do any harm to try moving it to Pin 17 instead just to see if it helps.

When you say the RGB wires are connected to the correct pins, have you checked from both ends of the cable using a multimeter? Without doing that you cant really be certain that all the connections are ok.

I cant really think of any reason why you get a picture with the N64 but not with the SNES, although I am leaning towards the YUV convertor being the culprit. I havent really looked into YUV convertors, but perhaps this could be something to do with the resolutions the SNES outputs? Most Saturn and N64 games use 240p:-
http://en.wikipedia.org/wiki/Low-definition_television
but SNES games seem to be all sorts of odd resolutions:-
http://en.wikipedia.org/wiki/Super_Nintendo_Entertainment_System#Video
Maybe your YUV convertor doesn't like these resolutions? You could try loading SNES games that use different resolutions to hopefully rule it out.

 

I changed the 5v wire to pin 8, reconnected the resistor(to pin 8 and pin 16), checked everything with a multimeter. Still nothing.....well almost. I had Star Ocean in the SNES and was excited when I saw the game start (with the large green E on the first screen) but it didn't do anything after. It just froze. With that it mind, I guess it may be my SCART to YUV. Oh well. When I get a moment I will try moving the ground wire and see what happens.

 

Wait, what froze? The game, or the TV screen? If the game froze then theres something not right with your SNES, if the TV screen then it could be the YUV convertor. Did the sound carry on playing?

A few questions that sprang to mind are:-
- Is the SNES using an official Nintendo NTSC SNES power supply? (SNS-002)
- Is the YUV convertor separately powered, or does it try and get its power from the SCART cable? (I dont know if any YUV convertors work that way, but I know some VGA adaptors do so :shrug If its trying to get its power from the SCART cable thats bad.
- Have you tried other SNES games? Especially ones that dont use enhancement chips (Stars Ocean uses S-DD1)
- Double check that the +5V wire (purple, now connected to SCART plug Pin 8) is connected to the MULTI OUT plug Pin 10 using the multimeter (It is possible to wire it to C-Sync, and SCART switching will work intermitantly using the DC offset present on the C-Sync signal - this is strongly not recommended but I have seen it happen when the cable manufacturer follows the port pinout incorrectly)