S-video mod on 800XL-Secam Rose - CA024969-001 - is it possible?

[JohnFante]

Well I recently got what I thought was a regular 800XL and today it was time to do a S-video mod .... I thought!

 

However, when I opened it up I found out that it was 800XL-Secam Rose - board revision CA024969-001. See attached!

 

Now I was wondering if it is possible to do a S-video mod on that board type? And if can I use the S-video combo cable that you can buy on Amazon. See picture.

 

 At the moment it outputs composite via a scart-cable. My RetroTink5X upscaler does good job with the output but my middle-aged eyes does not like it for longer periods of time
🤩

 

I read somewhere, after a quick search, that you can do a Sophia upgrade on the this board and improve picture quality. Is that right? And is it right that this version only has 128 colours? And is there anything you can do with that?

 

Any other mods/improvements I can do to improve picture quality?

 

Thank you in advance!

 

 

[Simius]

SECAM Atari have such a terrible picture that 128 colors instead of 256 no longer makes a difference. You can try an S-Video mod, but it won't get much better. The Sophia upgrade is a solution, but requires an adapter board because the GTIA and the FGTIA have a different pinouts.  

Edited April 27 by Simius
adding an attachment

[JohnFante]

4 hours ago, Simius said:

SECAM Atari have such a terrible picture that 128 colors instead of 256 no longer makes a difference. You can try an S-Video mod, but it won't get much better. The Sophia upgrade is a solution, but requires an adapter board because the GTIA and the FGTIA have a different pinouts.  

Thank you for your reply! Much appreciated!

 

How is the adapter board installed more precisely? Just to see how complicated the procedure would be and if I need more than a steady hand and a soldering iron 🙂

 

Feature wise I would - of course - get a much better picture with a Sophia2, but I would still only get the 128 colors the SECAM version can produce, and not the "normal" 256, or? And do that really make a difference? Are there software the SECAM version can not run? I am new to Atari 800's so this can be a noob question 🙂 

 

And last but not least: how much would an adapter board and a Sophia2 shipped to Denmark from you set me back?

[Simius]

Adapter board iinstallation is very simple - just between the Sophia and the MB .Without soldering.

After installation you get entire 256 color palette, but only via RGB and DVI. A composite output will be a luminance only. PAL color is possible but requires a system crystal replacement with 14.1875MHz one and several minor changes on the MB. 

I don't know a special SECAM software. Payment details on PM. 

[JohnFante]

27 minutes ago, Simius said:

Adapter board iinstallation is very simple - just between the Sophia and the MB .Without soldering.

After installation you get entire 256 color palette, but only via RGB and DVI. A composite output will be a luminance only. PAL color is possible but requires a system crystal replacement with 14.1875MHz one and several minor changes on the MB. 

I don't know a special SECAM software. Payment details on PM. 

Thank you. One last question 🙂:

 

If I want to use the RGB output for the Sophia can I do that via a scart cable? And is there a prebuilt cable for that, that includes sound? The reason is that I am thinking of putting the signal thorough my RetroTink 5X upscaler that handles all my retro computers via a scart switch.

[Simius]

There is no such cable ready to use. You can combine a dvi-to-vga and vga-to-scart cables but then there will be no sound. 

[JohnFante]

1 hour ago, Simius said:

There is no such cable ready to use. You can combine a dvi-to-vga and vga-to-scart cables but then there will be no sound. 

Ok. I can just get sound from the normal video-output. No problem 🙂 Money is on the way.

[Rybags]

How does Sophia handle TRIG input given that FGTIA does it serially through a single pin?

[Simius]

There are two solutons:

 

1. Special, SECAM core + simple, passive adapter (as on the picture)

2. Standard Sophia core + active adapter (still on paper)

[TZJB]

I have never seen one of these boards either, and although not relevant to the topic, it seems very similar to the 800XLF and may have the 100nF de-coupling capacitor C29 missing or not connected at the FREDDIE chip at manufacture. It would be wise to check continuity and if necessary add one across the 5V supply as close to FREDDIE as possible. Also short out L3 to improve the voltage to FREDDIE which will otherwise be below 5V. This was the case for my 800XLF where L3 came shorted out from the factory.