RGB cables, 5V and ground

[patroclus02]

For examplem MegaDrive AV out has lines for RGB, composite, sync and 5V and ground. When you make a RGB cable, do you need the 5V and / or ground line ??
Sync is also needed for RGB?

thank you.

[martianviking]

No, you don't need the 5V line.

EDIT:  I took out the part where I said you didn't need ground.  I apologize; I'm not sure why I said that.

[patroclus02]

so why are they included?

[phreak97]

just in case

[NFG]

No, you don't need the 5V or ground lines. For a useful RGB output, you only need the R, G, B, and sync signals.

Whoah there, don't be telling this story any longer.  Ground is mandatory for every electrical circuit.  +5v is available on the output to drive optional components (like RF switches) and is not needed for RGB, but GROUND is not an optional thing.

[patroclus02]

That's what I thought, because no circuit works without ground.
So, I need R,G,B, sync and ground signals, isn't it? along with audio, of course.

what does impedance mean in pinouts?, for example, in this table??
http://www.bnoack.com/index.html?http&&&ww...art-pinout.html

thanks

[Hojo_Norem]

+5v is available on the output to drive optional components (like RF switches) and is not needed for RGB

Unless you want to make a SCART RGB cable! ^_^  

[gannon]

Also, some older tvs need the +5V. I'm not sure why this is, but for the most part they don't.

[RARusk]

The +5VDC can be used to power sync chips (like the LM1881, the EL4583, or the EL1883) which is a requirement for the PS1 and PS2.

[Darklegion]

You can just use any of the r,g,b wires for the fast blanking pin,they normally provide the correct voltage.....unless they are overly weak or strong.And that again depends on the TV,many don't stick to the scart standard correctly....It might be better to use 5v through a resistor though,I am not sure if there are any effects from crosstalk or the like from running them together but I imagine it might affect something......many do it this way with fine results however..And yes it is handy for running additional circuits,mine are all handmade though so I can just take 5v from wherever I want

[patroclus02]

http://www.gamesx.com/misctech/mypin.htm

Here, there's no GROUND wire...
but here, a SMS RGB cable, there is.
http://www.mikeg2.freeserve.co.uk/masterful/rgb.html

Um.. I'm really confused... Is it only me? Can anyone tell me which way is correct?
also, what about cable shield? should be conected to ground?
Thanks!

[NFG]

The outside of the connector is used for Ground.  This is normally used as a shield-ground in addition to normal ground, but I ran out of pins (and it doesn't really matter how many grounds you have as long as they're well connected).

I should mention that.

[patroclus02]

ah! ok!
So, last thing is what about 5V.
In the SMS to RBG, he uses it as RGB switching (for SCART conection only).

[Guest]

So, last thing is what about 5V.
In the SMS to RBG, he uses it as RGB switching (for SCART conection only).

Those TVs that change automatically to RGB on SCART, uses pin 16 to determine if the source (SNES, PS2 or whatever) is outputting an RGB signal. Soldering the 5V wire to a resistor (my SCART cables use a 75ohm resistor) and then the resistor to pin 16 solves that problem. If the TV doesn't get any current on pin 16, it will use the composite signal that is being sent along with the sync.
That site you mentioned earlier, says the RGB switch is on pin 8, which is nonsense. Pin 8 is used for automatically switching your TV to SCART whenever you turn on your console.