You should spread this around the Amiga newsgroups.

As some of you might know a few weeks ago I ordered an lead to take an Amiga to an LCD via a SCART socket. While these work fine on normal TV's, many users report problems with LCD's. The official solution (including from the people who sell the leads) was to use a CRT instead as they would give a better picture.

But one Amiga fan didn't take this lying down. Why did LCD's play up? Why were my whites shimmering? As someone who works with video all day long I know its perfectly possible to have voltages that are so high they cause problems. But I was assured that everything the Amiga outputted was within spec. Hmmm.

After some testing with a multimeter I found the voltage on pin 20 of the SCART was quite high. I ordered a big pack of resistors and just spent an hour fiddling with various values.

In short I've found that if you wire a 220 Ohm resistor to pin 20 of the SCART the shimmering white problem goes away.

Now the picture is still not rock solid clear like the Dreamcast or Megadrive but I suspect there may be other problems with the Amigas output that need taming.

But for the time being, if you are an Amiga fan with an LCD and your piccy is looking shit, try a 220 Ohm resistor on pin 20.


[nb] This is quite separate to the switching issue which my lead already had a resistor fitted for.

Even though I haven't tested my Scart cable yet, I'm sure I'll have the same problem. However I am a cable and soldering inadequate.

I saw a video of some dude who had modified his amiga to output VGA. I remember him saying that the standard RGB looked like shit on whatever screen he was using. He just opened up the amiga, tapped into the RGB lines and fed them into a convter board, I think.

And start selling special Amiga to LCD cables.

Get an A1200.

You should spread this around the Amiga newsgroups.

You are right in saying there are problems with the Amigas output. The guy who sells the leads insists everything is in spec, and while it might be I actually think the RGB levels (and sound levels come to that) are high. But I'll be fucked if I'm wiring resistors to every pin. The black level is certainly elevated. It looks akin to NTSC black displayed on a PAL monitor.

If I had to guess I'd say the signal voltage is too high AND there's too much impedance in the output. So the effect you get varies depending on what you hook up to it - some CRT monitors are clearly fine, but a modern LCD monitor requires no current as it's not actually driving anything, so the levels aren't attenuated and appear too high.

Either that or it varies from Amiga to Amiga, which wouldn't surprise me in the least.

what did the cd32 output? Rf or composite i assume

Ah, I assumed RGB was RGB. But that explains it.

CRT sets will have a set of buffers with the gain connected to the "brightness" control for a start, so that helps.

I wonder if some LCD TVs cope with this better than others. Anyway, you found a workable solution...

RF, S-Video and composite (from memory).

I've said it so many times but when Amstrad stuck a full RGB SCART socket on the GX4000, it was the most logical and well thought out inclusion of a socket on a computer/console ever. No proprietary leads, just plug and play. So why the fucking fuck did everyone else find it so difficult?

Referring back to the original problem, and excuse me if this is a bit of a thick suggestion, but couldn't one tame the signal by routing it through some sort of SCART switching box?

Through the mists of time I am fairly sure that there are inconsistencies in output between different batches of A1200s based on cost cutting and who actually manufactured them.