Re: [stella] Cybertech Videoboard

Subject: Re: [stella] Cybertech Videoboard
From: resqsoft@xxxxxxxxxxxxx
Date: Thu, 11 Mar 2004 13:38:29 -0800 (GMT-08:00)
It is actually more like bleeding. I see it most prominant in games like Space invaders (Actually Space Invaders Vector edition does it the most). I also see red on the edges (your "color blip"?) in Pitfall 2 where the yellow transitions to green or brown graphics. So which pot is the saturation? While I am asking... what do all the pots do?  

No problem on the 2600 models as I have a dozen or so of these :-) Maybe I should 
Hope no one takes these messages the wrong way. The video works great. I recommend it. I may be just a bit too picky ;-)

Actually, I am kind of interested in John Seager's comments. Perhaps, I need to take a field trip to his place. He has been anxious to show me his new home for a year now.


-----Original Message-----
From: Chris Wilkson <ecwilkso@xxxxxxx>
Sent: Mar 11, 2004 12:14 PM
To: stella@xxxxxxxxxxx
Subject: Re: [stella] Cybertech Videoboard

I've found that the socketed chip sets are kinda hit and miss.  It is hard
to find a cut off point for socket vs. no socket.  I think I did say at one
point on Atariage that not all TIAs are socketed, but I couldn't really
nail it down.

In general:
 6 switchers are socketed.
 most woodies are socketed.
 my only Vader is socketed, but that doesn't make a legit data sample.
 almost all JRs are NOT socketed, but I have seen more than one with sockets.

These are not rules...Atari went through too many management and design
changes to be consistent.  :(

Regarding the color issues.  Is it ghosting, bleeding, or both?  The
difference is that ghosting is actually a duplicated image while bleeding
is a single smeared image.  You can help bleeding by turning down the
saturation on the CyberTech card.  Same effect as turning down the "color"
control on your TV.  I would be really surprised if there is any ghosting.

One other possibility is a color blip.  (my own non-technical term)
This occurs when the 2600 switches from one color value to another.
Color is encoded as phase in the chroma signal.  A sample chroma waveform
is shown below, with 3 examples of a color change:

/\    /\    /\  /\    /\    /\      /\    /\    /\  _    /\    /\
  \  /  \  /  \/  \  /  \  /  \    /  \  /  \  /  \ |\  /  \  /
   \/    \/        \/    \/    \/\/    \/    \/    \| \/    \/

               |<-- 120 deg.     |<-- 240 deg.      |<-- 240 deg.

The runt peaks in the first 2 examples might not be detected, resulting
in a single gray pixel (no color).  The 3rd example could result in a
completely unintentional color for one pixel.  Check the right side of
the trees in Pitfall II for the gray pixel effect.  This kind of thing
can't be helped, no matter what you do.

If you can be a little more specific on the things you're seeing, I'll
be able to give more help.


On Thu, 11 Mar 2004 resqsoft@xxxxxxxxxxxxx wrote:

> Hi Chris,
> Maybe I missed this, but did you ever give a list of 2600s that this mod won't work with (perhaps they work, but require a bit more  tinkering). The reason I ask, is that I recieved mine yesterday and promptly tried to install it in one of my 4 switch "Vader" units. Unfortunately all the chips are soldered on the board. I did have another unit to do the mod on and it went very quickly.
> BTW: It installs really easy and looks really good. I have only 2 minor complaints. One being that the board is a really tight fight to get into the sockets. The other complaint I have is the color bleed (ghosting) on the edges. Although very minor compared to the vast improvement in video quality it provides, I am striving for a picture like you demonstrated at CGE.  Can this be adjusted with the pots?
> Here is a link to my video board in action:
> The variance in colors on the Imagic unit really test the video. Pitfall 2 is my other test article. Both look great.
> Regards,
> -Lee
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