modded gamecube scart cable RGB switch fix

[Papercut]

A lot of modded GameCube RGB scart cables are wired up like this:

pin 8 of the scart plug to 12v from the digital av port.

pin 16 (RGB switch) to 12v from the digital av port via a 75 Ohm resistor, giving approx 6v.

The RGB switch voltage should be 1-3v and not 6v, so some fussy TVs won't switch to RGB properly with 6v on pin 16.

The resistor should be around 375 Ohm, which will give you 2v (forms a potential divider with the 75 Ohm impedence on pin 16).

If you have a modded rgb scart cable that doesn't switch to RGB mode properly, check to see if you have 12v connected to pin 16 of the scart plug through a 75 Ohm resistor. If you do, replacing it with a 360 or 390 Ohm resistor (standard values) should fix the problem.

I figured this out to solve Crono's problem here:

http://ntsc-uk.domino.org/viewtopic.php?t=12222

[rob]

Papercut, does this go for the modded panasonic Q rgb cable aswell?

I recieved one today but im getting no picture/sound but my telly is detecting the rgb signal. think ive got a fussy telly

[Papercut]

Papercut, does this go for the modded panasonic Q rgb cable aswell?

It does yes.

I recieved one today but im getting no picture/sound but my telly is detecting the rgb signal. think ive got a fussy telly

Hmm, you should get audio at least. Have you tried switching to AV manually?

Doesn't sound like an RGB switch problem, sounds more like a not switching at all problem.

[rob]

what do you mean by switching too av manually?

sorry i sound really thick but im not up with all this!

im not too fussed about the audio because i plan to get an optical lead later this week.

[Papercut]

well, what happens when the GameCube turns on? Does the TV switch to external AV mode?

[rob]

when i turn the Q on, it does go to the AV mode automatically and the logo with the three dots on it comes up to tell you that the rgb sgnal has been detected but there is just a black screen apart from that.

[Papercut]

hmm, but you don't hear audio?

thats pretty odd. it could be the rgb switching voltage then, but you would expect to be able to hear it.

can you run other rgb stuff ok?

[rob]

Yes. I run both my jap DC and Pal X-box thru rgb scart.

im just trying my Q thru the crappy yellow/red/white cables, so at least i know the Q works.

do you think i should follow your advice that you posted at the top of this subject then?

[Papercut]

do you think i should follow your advice that you posted at the top of this subject then?

probably worth a go. if you do change it, be careful, measure the voltage and existing resistor value beforehand if you can.

cheap multimeters are ?5 a pop at maplins,

[rob]

think i will get a shop that i know who does cables to do it for me.

thanks for the advice papercut, much app.

[rob]

Hi Papercut. ive tryed my Q on my mates Panasonic "32 w/s telly & the best we could get on that is a black & white picture(was rgb quality tho).
Av tryed it on some small tellys & the picture was rolling. On my telly(Sony "32 w/s) it is still just a black screen.

I havnt done anything to the lead yet, do you think theres a possibility its a faulty lead tho?

[Papercut]

That does sound odd.

Normally black and white picture means the TV can do 60Hz but not NTSC color, and the video signal is composite video.

A rolling picture will be down to a TV that doesn't support 60Hz.

[Shadow_Zero]

I've got the same problem!
Got the Q RGB cable today from Lan-Kwei.
When I turn on the Q it automatically switches to the A/V channel. The screen remains blank and I have no audio.
Is the problem arised yet? (and a solution?)


Btw, I have a Philips 28" widescreen tv and the RGB of my SNES works fine.

[Papercut]

are you certain its RGB you're getting out of your snes and not composite video?

the post at the top of this thread describes the solution to the problem with some TVs that require a correct RGB switching voltage to display RGB from a scart cable.

I can't tell whether thats your problem or not, but it might be.

Normally though, even if that was a problem, you'd still be able to hear audio.

As I said to rob, it might be worth checking voltages and resistors to make sure.

[Shadow_Zero]

Well, unless my tv is lying to me the SNES is really in RGB
When I switch on my SNES the tv says "RGB".
I cut out the capacitors to get rid off the dark image and the difference between composite is considerate.

I assume the RGB SCART provides audio, or do I need to use the seperate phono connectors?

If my SNES has proper RGB, is the solution on top of this thread still an option or not?

I don't feel much for opening the cable, but if there's no other way I might give it a try...