Atari 8-bit to S-video cable question

[Dean Garraghty]

Hello All,

I've just put together an Atari 8-bit monitor socket to s-video (4-pin
mini-DIN) cable for my own use. Tried it on my 800XL, 130XE, and 800 (PAL
machines). It didn't work fully on any of them. The 800XL was in colour, but
the colours bled badly. White came out with green and blue shadowing, with a
thick green stripe down the left hand side of the screen, and a blue one at
the right hand side when on the standard Atari blue background with READY at
the top. The 130XE was better (no stripes) but still had a degree of colour
bleed around the white text. The 800 was the worst of the lot. It looked
like black&white at first, but it was in colour, but faded. Tried on 2
different TVs with the same effect.

Anybody had this problem? It appears that not all machines have the
chroma/luma connected, but I've not read of any problems of this nature.

Dean Garraghty

[stephen...@hotmail.com]

I've been planning to do the same thing for a few days now (for an 800,
NTSC). I just haven't gotten around to it yet.

>From light reading on this subject I've learned that some or all 800XLs
had chrominance disconnected substituting composite video instead at
pin 5 (or disconnected, not sure which) on the DIN connector.

I assume you only built a simple cable, Atari DIN to S-Video, and
didn't look into Ben Poehland's Super Video mods 2.0 and 2.1 for the
800XL or Charles Cole's mod for the 130XE (see links).

I think the mods are necessary to obtain satisfactory S-Video output
(no bleeding) with the 800XL and 130XE.

Your result of seeing only Black & White output from the 800 seems to
indicate you just have a basic wiring problem. I got that same result
when I accidentally reversed two connections of an S-Video connector
(for a different project). I don't recall which pins I
cross-connected, though.

I haven't been able to find equivalents of the Super Video mods for the
800 so I'm just going to try making a basic S-Video cable for my 800
and hope for the best. I'm starting it right now.

I'll let you know my results.

Links to the aforementioned articles can be found at Clarence Dyson's
Atarimods page.

http://www.geocities.com/atarimods/atari.html

Steve Sheppard

[Kryten]

Hi Dean.

http://www.howell1964.freeserve.co.uk/Atari/800XL/Atari_800XL_Video.htm

Sounds like your TV is trying to lock onto a chroma signal that isn't there.

It may be that the chroma signal is not on the right pin, but bit of it
leaks into the luma signal so that it doesn't turn off it's colour circuits.

The cable is easy enough to make.

You will have to check the cable and that the chroma is wired to the socket.
Atari only wired it on their late machines, so that is highly likely to be a
cause.

[stephen...@hotmail.com]

My cable is done. Just as with my other project I got pins 3 and 4
mixed and was greeted with a ugly, rolling, B & W image. When I got
the connection right the picture was beautiful.

This S-Video connection is far superior to the RF and composite video
connections I was using earlier. There is far less noise, almost none.

My situation may be unique. I'm using an original ATI All-in-Wonder
video card, part of one of my PCs, not a standalone television or
monitor. The RF and composite video connections using the AIW were
producing unacceptable herring bone patterns with one and random noise
with the other. This is why I wanted to try the S-Video modification.

Dean, none of what I said answers your question. I don't know the
answer. Sorry.

Steve Sheppard

[Slor]

Despite all prevention efforts, stephen...@hotmail.com wrote in
news:1108306555.0...@f14g2000cwb.googlegroups.com:

>
>>From light reading on this subject I've learned that some or all 800XLs
> had chrominance disconnected substituting composite video instead at
> pin 5 (or disconnected, not sure which) on the DIN connector.
>

There is a very simple mod to connect the chroma line on the 800XL. It
won't be as good as the 130XE picture (or the supervideo mod), but it looks
substantially better than composite output. I did this by simply running a
jumper from the R66/R67/R68 junction to the croma lead on the video port.

Also, I have found that, at least with my setup, S-video cable quality
makes a WORLD of difference in the picture I get, so make sure you use the
best components you can get your hands on!

--
Slor

[stephen...@hotmail.com]

Slor, you should be able to tell me, once and for all, what is the
default connection at pin 5 of the 800XL's video connector? It's
supposed to be composite chroma but is it actually composite video? or
or no connection?

Steve Sheppard

[Slor]

Despite all prevention efforts, stephen...@hotmail.com wrote in

news:1108327335....@o13g2000cwo.googlegroups.com:

This article should answer some questions, including the "pin with no
connection" and "color smear with a green tinge" if you try using what's
there.

http://www.atarimagazines.com/v5n7/xlcolorboost.html

--
Slor

[stephen...@hotmail.com]

Hmmm, no connection on pin 5. Now I'm confused. Dean should have seen
color on the 800 and B & W on an unmodified 800XL. Not the other way
around.

Steve Sheppard

[Rick D.]

Hello,

While I can't offer any info on the pal problem, a general suggestion is to try
the TVs with some other svideo device, a vcr or camcorder.

Do the A8 computers have the same display using RF or a regular composite
monitor?

What quality of cable are you using? How about shielding the lines?

The monitor jack pinout clockwise is luminance, video, ground, chroma(not XL),
and audio. Svideo normally goes to luminance and chroma, but will work with
luminance and video. I have found that the other two svideo pins goe to a
common ground with the shield.

Rick D.