Photon's RGB Scart cable

[Photon]

Mainly because I've seen various advice and bought a cable that didn't work, and I made two more cables today that worked right away with 1 monitor, 1 32" CRT TV, and 1 13" LCD TV using the same simple wiring, I thought I'd share a cable that seems like a very alternative cable (?)

Now, if you want the best picture for Amiga you take its RGB output and nothing else, and display it on an RGB capable display and nothing else. PAL RGB is the ticket! With the possible attachment of the word 'Scart' (I take such filthy words in my mouth but rarely) at the end. Now, if I'm lucky enough to find a display that takes PAL RGB, how do I make a cable that this display likes...?

I made the first cable in 1990-1991 for my C1081 and I didn't half expect it'd work with a 1999-ish CRT TV nor a 2002 LCD TV, but since it did I thought I'd share my entry for the 'cables that work' thing that I thought was so simple but many have problems with/solutions for. Maybe it's already known, but you wouldn't think so from misc. problem threads. And certainly HD displays may be incompatible with it, but I wouldn't use them for displaying Amiga since I know the aspect ratio of my Amiga. ...Or something along those lines.

-~-

First of all don't connect the shield grounds and voltages, because you will be connecting your Amiga's limited-Amperage voltages with an unknown that doesn't need them, and the shield GND connection problem is familiar to anyone who's connected stuff in a music studio. Plenty of docs on Wikipedia. Don't connect the digital GND because you want only the analog outputs to be a part of the TV's circuit.

Secondly, use the _CSYNC as Composite Video and RGB _CSYNC, and don't add any resistor to lower the voltage to nominal 1V as I've seen in some.*

Thirdly, don't connect separate r/g/b GNDs. They'll all be connected internally in the Amiga, and to the Amiga's shield GND, so a better option is to connect them all together at the Amiga video connector (pins 16-20) and use the shield of the cable as a suitably high gauge wire to conduct it. This will ensure that you get no shadowing of high contrast graphics when the cable is longish (defined by me as 4-10m). Don't use shielded multiwire cables where the wires are very thin (4-6 strands) as this will make the cable resistive and prone to shadowing also, if the TV has capacitive circuitry at inputs.

Do connect the audio with proper RCA plugs like these

(they are hand-pinchable and so will always make good contact). Some of the "generic TV store consumer" RCA cables have "headset-thin" cables as well so get ones from a quality store. I actually had to replace the audio cable on the Amiga-to-Scart cable I bought to not get 'brrrrr' sounds at medium volume levels.

Pinout with coder colors (yEaHh!):


-~-

The problem with Scart is that it tries (tried?) to be a grand unified theory of connecting everything, at which it fails miserably blending misc signal standards, and adds a terribly designed connector to boot. Can't be easy for the TV manufacturers either. A better option then, was to strip it down to the essentials and get it to work.

I'd love feedback on this! (Note that I'm not sure I've posted anything special at all, at any rate I would advise against going by the extrapolated information in the below pinout links.)

Also, I'm especially interested if you've found TVs that this pinout does NOT work with.

Amiga Video Pinout
Sc*rt Pinout

* Because it doesn't work like that, unless you have the schematic of the TV and it shows adding in a resistor will make it like the sync levels. The displays I tried happily accepted the sync as-is and in fact allowed RGB display in "Same AV Channel but S-Video" mode, resulting in a centering of the display rather than the classic "left edge of CLI window a little too much to the left" that we all know and which is normal.

[orange]

[Photon]

Rolleyes face with no comment. Well I've given you every chance Orange.

Suffice to say that there is so much discussion going on about the Ultimate Cable!? And this is my bid to instead of trying to accommodate all types of displays and never really getting the hang of why it fails, to try this reduced-to-minimal cable and save the hassle.

I really think this deserves a shot at Actually Working Scart Cable (and simple to do).

This cable worked on 3 displays of different type and age without a hitch, where the store bought cable failed on all 3 with the same symptoms. I slaughtered the cable by nipping off all the unnecessary cables and making it like mine, and it worked on all 3.

I really think this reduces it to where you don't get incompatibilties, where the only requirement is that the display support RGB PAL, and removes a lot of issues. At the same time I don't think I've done anything special at all. It's the way it's supposed to be, anything else is catering to whims of Chinese makers of cheap flatscreens who, let's face it, don't have a clue about PAL these days.

I'd really like it if someone applying the very latest research findings of Ian and finding that the cable just doesn't work, would try this one and say if it fixed it!


Select input and format with the remote, and steer clear of issues. With this cable, you know if it's the TV or your soldering, because it's so simple.

[roy bates]

yes it does work photon mine doesent have the resistor,and works on all the lcd tv's i have.

[e5frog]

Doesn't seem very strange, but why not use the +5V (or +12V) from the Amiga and a resistor to get a stable and proper 1-3V signal on pin 16 to indicate that you have an RGB signal?
Or does the /CSYNC stay between 1-3V all the time?

Usually if you want the TV to switch automatically when turning the Amiga on you'd want to put 12V on scart pin 8 as well.

[Photon]

The point is, if you play with voltage levels you put yourself in the hands of RandomBrand(tm) TVs, which usually suck at compliance to any standards. I have to use the remote to get the TV to power up from standby anyway. Why not press the AV button to power it on, and you're done?

Just posted this cos I didn't see what all the fuss was about.

If you buy a TV that has a brand name that you've ever heard of in your life, and it has two SCART inputs, the lower AV1 will accept RGB input and work fine with just R, G, B, sync, GND. The exact same cable worked perfectly today for a Thomson 22".

Sorry for the thread necromancy I missed your reply there e5frog.