Recently I setup a few of the computers from my retro computing collection. Along with the Amiga 2000, Apple IIc, and Macintosh Plus was the Atari 800XL.
![Atari 800XL, Macintosh Plus, Amiga 2000, Apple IIc](http://paulrickards.com/wp-content/uploads/2013/03/photo-2-800x800.jpg)
I’ve not used it all that much and thought it deserved a little hands on time. When I acquired it I also purchased a 5 pin DIN plug for the video jack on the rear to bring out stereo RCA audio (although it’s just mono) and s-video. I was puzzled when I plugged it in and turned it on to find that the video was only in black and white. I switched to the RF modulator and saw color so I knew the computer was working fine. I searched and discovered that some (maybe all?) Atari 800XL’s have provisions for s-video, namely separated luma (brightness) and chroma (color) but Atari neglected to connect the chroma to the plug. This explains why the image has no color.
![Atari 800XL, Macintosh Plus, Apple IIc, Amiga 2000](http://paulrickards.com/wp-content/uploads/2013/03/photo-1-840x629.jpg)
I searched and was surprised that I didn’t find all that much information on the subject. One site called the seemed to have the most information but I found the directions confusing and images that were hard to see. I kept searching and found a clear forum posting on AtariAge (post #8), also summarized below.
- REMOVE C56 capacitor (if present)
- Lift C54 right-hand side, preferably by inserting an on-off switch (if you want to preserve composite out).
- On the underside of the motherboard, solder chroma-signal wire from R67/R68 junction, to chroma pin in video DIN port pin 5. Follow the cable pathway exactly as shown so the RF shielding fits back on.
- Adjust brightness/contrast/saturation on your monitor. Don’t underestimate this step as I did at first. It’s important and made all the difference in the quality of the final picture.
![Atari 800XL motherboard with chroma signal patch](http://paulrickards.com/wp-content/uploads/2013/03/photo-4-840x629.jpg)
With those small changes, I now have crisp s-video output from my Atari 800XL to an LCD monitor. The picture looks fantastic!