Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!rutgers!mit-eddie!genrad!decvax!decwrl!star.dec.com!fisher
From: fisher@star.dec.com (Burns Fisher ZKO1-1/D42 DTN 381-1466)
Newsgroups: comp.sys.atari.8bit
Subject: Chroma/Luma on 800XL
Message-ID: <7398@decwrl.DEC.COM>
Date: Wed, 7-Jan-87 10:16:22 EST
Article-I.D.: decwrl.7398
Posted: Wed Jan  7 10:16:22 1987
Date-Received: Wed, 7-Jan-87 22:48:24 EST
Sender: daemon@decwrl.DEC.COM
Organization: Digital Equipment Corporation
Lines: 31

A raging (well mild) debate has been going on around here regarding the 
presence or absence of a chroma signal on the 800XL video output.  Could
someone give a reasonably technical explanation of what the situation is?

Synopsis of the argument:

An article a few years ago in Antic says that XLs don't have chroma.
However, it appears that when you hook up the luma/chroma output pins to
the luma/chroma inputs of a monitor, it works.  There is some confirmation
for the Antic side if you look at the board.  There are four connections to
the video jack.  This is just right for Composite/Luma/Audio/Ground; no room
for a chroma signal.

There are also references floating around to the fact that it is possible to
get the chroma signal with a magic capacitor or two, but nothing definitive
has surfaced.

Questions:

1.  Is it true that there is no chroma on an 800XL?

2.  If so, what IS happening when we make connections to the chroma input?
    (For example, does composite into the chroma input have the same effect?)

3.  Can we get chroma via hacking?

4.  Does it matter?

Thanks.

Burns