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Quick & Easy Video Upgrade for the 1200XL?


Larry

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PAL Antic would likely make no difference.

 

GTIA handles colourburst in any case. To get a 1200XL converted to PAL you'd need the 4.43 Mhz crystal like all other PAL units have, then you'd need to hook in whatever parts of the circuit feed that signal to GTIA.

 

Not sure either if an NTSC GTIA will pass through the different colour clocking if you supplied it, I think by default it just generates the colour signal from the system clock input/s.

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  • 10 years later...

I'm going to resurrect this thread...

 

At this point I am very confused. I see several different ways to clean up the video signal on the Atari 1200XL. Even in this thread there are differences in how it is done... For example, do I use R44 (which end?)or R45 (which end?) or the left side of R186 for CHROMA to pin 5 of J2.

 

There is an undated CLRPIC 2 mod located here: AGH -- Atari 1200XL Bad Video Fix (atarihq.com)

Then there is CLRPIC v128.3 from May 2002 located here: The Atari 1200XL Computer Systems (atarimuseum.com)

Don't forget the SuperVideo 2.1 from Dec 1993 here: Super Video 2.1XL (pigwa.net)

 

Which is the most relevant and best fix?

 

There is a switch in the SuperVideo 2.1 mod - Do I want the switch closed or open for the clean video? Why do you even need a switch?

 

... and, if I do one of these mods and later decide to get a UAV, will I have to undo the mod first?

 

This is relative to the NTSC Atari 1200XL, at least for me.

Edited by Calab
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1 hour ago, Calab said:

There is a switch in the SuperVideo 2.1 mod - Do I want the switch closed or open for the clean video? Why do you even need a switch?

The switch has to be closed to output composite video, but should be open when using s-video. This is to isolate the chroma and luma signals from each other when using s-video, otherwise there would be interaction between the signals which could have a negative affect on the s-video signal.

 

The FMS6400 based and UAV video upgrades each use an IC designed for video signals to achieve this isolation without the need for a switch.

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I have accomplished the CLRPIC v128.3 from May 2002 (a.k.a ClearPic2002) on several 1200XLs and find the output to be quite acceptable.  You can easily read 80 column (The Last Word) and Omniview.  In games, colors are crisp and edges are sharp.  The UAV is a bit sharper with 40 column text, but I'm looking at it on a 46" TV, so on a monitor, the difference should be indiscernible.

 

Edited by ACML
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You can get pretty good video just by replacing L15 and C115 with a wire (I use 1 ohm resistors - looks cleaner) and pulling C60. You might like to leave in C60 for a softer look. Add a wire from the LH side of R186 to the empty pin on the video connector, J2. This connects the CHROMA line for s-video.

 

Don't forget to replace R63 with a wire. This restores +5v to the SIO.

 

Bob

 

 

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1 hour ago, bob1200xl said:

You can get pretty good video just by replacing L15 and C115 with a wire (I use 1 ohm resistors - looks cleaner) and pulling C60. You might like to leave in C60 for a softer look. Add a wire from the LH side of R186 to the empty pin on the video connector, J2. This connects the CHROMA line for s-video.

I will give this a try. Easy to do and reversible. 

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Well, I ended up doing the CLRPIC2 mod, as I had all the parts for it, but I tried the simple 3 component fix first. Here are closeups of my TV, connected via SVideo.

 

The BEFORE picture really looks washed out and blurry.

The Simple fix is definitely cleaner.

The CLRPIC2 fix seems brighter.

I don't think I'll do anything more for the time being. Eventually will be getting a UAV and a Sophia2, if possible.

 

Before:

Before.thumb.jpg.371fc0b2b56c801087c5efb451bb427a.jpg

 

Simple fix:

Simple.thumb.jpg.03dcd4292902cf57f792b6e8dc346257.jpg

 

CLRPIC2:
CLRPIC2.thumb.jpg.b5c24c04e5f9a733b698623a70d6c043.jpg

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9 minutes ago, Calab said:

Well, I ended up doing the CLRPIC2 mod, as I had all the parts for it, but I tried the simple 3 component fix first. Here are closeups of my TV, connected via SVideo.

 

The BEFORE picture really looks washed out and blurry.

The Simple fix is definitely cleaner.

The CLRPIC2 fix seems brighter.

I don't think I'll do anything more for the time being. Eventually will be getting a UAV and a Sophia2, if possible.

 

Before:

Before.thumb.jpg.371fc0b2b56c801087c5efb451bb427a.jpg

 

Simple fix:

Simple.thumb.jpg.03dcd4292902cf57f792b6e8dc346257.jpg

 

CLRPIC2:
CLRPIC2.thumb.jpg.b5c24c04e5f9a733b698623a70d6c043.jpg

Are you using S-video output (Y/C)?  I always get a really nice sharp image with ClearPic2002.  The example almost looks like composite out.

 

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9 minutes ago, ACML said:

Are you using S-video output (Y/C)?  I always get a really nice sharp image with ClearPic2002.  The example almost looks like composite out.

I'm using the Luma/Chroma signals to S-video on my Toshiba TV. I don't have a cable with RCA jacks or I would have tried on my Amiga monitors. Then I'm also taking the pictures with my cellphone.

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1 hour ago, Calab said:

I'm using the Luma/Chroma signals to S-video on my Toshiba TV. I don't have a cable with RCA jacks or I would have tried on my Amiga monitors. Then I'm also taking the pictures with my cellphone.

Choice of components does matter.  I tried using surface mount caps the first time and the image quality was not so good.  I switched over to old ceramic caps and the picture looks great.

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