Path: utzoo!attcan!uunet!cs.utexas.edu!mailrus!jarvis.csri.toronto.edu!utgpu!watserv1!watmath!att!cbnewsd!njd
From: njd@cbnewsd.ATT.COM (nick.j.dimasi)
Newsgroups: comp.sys.atari.8bit
Subject: Re: Connecting Atari 800 to a video input
Message-ID: <13178@cbnewsd.ATT.COM>
Date: 13 Feb 90 23:55:30 GMT
References: <10@xyzzy.UUCP>
Reply-To: njd@cbnewsd.ATT.COM (nick.j.dimasi,ix,)
Organization: AT&T Bell Laboratories
Lines: 51

In article <10@xyzzy.UUCP> roths@dg-rtp.dg.com writes:
>[would like to connect his Atari 800 to a television using video input]
>I have a cable that I used for that purpose years ago.  One one end, the
>cable plugs into the Atari 800 monitor jack.  The other end has 4 outputs
>that look like standard audio/video connectors.  They are yellow, black,
>white, and red.
>
>The only two which give any results are the yellow and black ones.  The black
>one works perfectly, it sends an audio signal to whichever audio input I attach
>it to.  The yellow one does send a video signal to the television.  But the
>picture is in black and white and appears to have other problems as well.
> .....

I think I know what's happening (any 800/video gurus out there care to confirm
and/or correct the following?):  

First:  the 800 has (at its monitor jack) composite video
(NTSC, at least in the USA) output and audio output.  (I used to only have
an 800 but it's cost-to-repair got too high, so off to K-Mart for a $99.95
800XL.)  I think that the audio is the same pin (on the DIN jack/plug) for
all the 8-bits, if so that explains why any 8-bit-Atari-compatible monitor
cable will give you audio.  

Second:  Your video cable sounds a lot like one that has,
instead of _composite video_, what I call "split chroma/luma" video. The
"luma" [luminance] signal [same idea as Graphics "luminance"] is brought out 
separately from the "chroma" [chrominance] signal [same idea as "hue" I think].
This kind of cable is what us 8-bit users who have a 130XE (I don't know about
the 65XE, but I don't know anyone personally who has one) or an XL with the
chroma signal brought out (a simple h/w mod.) use to see the highest-resolution
COLOR display that those computers can put out (using a monitor like the
Commodore 1702 or 1802, Technika[sp?] <whatever-model-#>, etc.).
The only flaw here is that your cable has _four_ plugs.  Maybe one of them is
supposed to be composite video; but if so, and if the connection was good
(and the cable is wired properly - sorry but I don't have the 800's pinouts,
at least not here at work), you should be OK.

Third:  Your Atari 800 (as you may have inferred from the above) _does not_
put out split chroma/luma (unless it has been modified to do that, much more
complicated than for an XL I think).  So again, you need a cable for plain
vanilla composite video.  (These used to be available at any 8-bit-anything
computer dealer, even like discount stores...)

I hope this helps!

Nick DiMasi				Uniq Digital Technologies, Inc.
...clout!udt386!nick (not currently read often) (Internet reg. pending)
...att!odutsa!njd (READ WEEKDAYS)	DELPHI: TURBONICK
				   |
DON'T USE R/r (reply command)!!!   |	under contract to AT&T Network Systems
				   |	(Network Software Ctr., Lisle, IL)