I have modified my 7800 system so that I can connect it to an AV output. It works :D :D I did this mod in the spring so it was about time I put it in here
Here I build a new circuitboard for the sound and picture circuits so that they can be connected to the AV jacks that goes to the TV.
(http://pici.se/pictures/PtZFyTdue.jpg)
The blue cable is soldered to the GND on the mobo. The red one is connected to the GND on the RCA jacks. I also put on some rubberfeet on the other side of the curcuitbaord so I can place in on the mobo without it getting in contact with other circuit's on the mobo.
(http://pici.se/pictures/RaevWIeGI.jpg)
Here, I connect the sound from the console to the new curcuitboard.The black cable goes to the upper side of the C14 so that I can take out the POKEY sound and connect it to the RCA. The red one is the sound itself from the C10
(http://pici.se/pictures/IoSRYWFwl.jpg)
I had to remove this while soldering the POKEY cable but luckily it only takes 2 screws to remove/put it back.
(http://pici.se/pictures/XfgzGtAyc.jpg)
Here is the whole system with the new AVboard connected to the mobo. However I changed 2 of the cables in this picture, the one that gives 5 V and the video-input.
(http://pici.se/pictures/SLkUzSnCS.jpg)
It may be stupid by Atari to not using AV connection from the beginning but they on the other hand put an AV-modifier hole on the side so the cables can go out that way after put back the RF shield together
(http://pici.se/pictures/UwNtbtyeX.jpg)
The cables gets soldered to the RCA jacks
(http://pici.se/pictures/RwoWjsVKM.jpg)
So it is...
(http://pici.se/pictures/yusrgmpma.jpg)
Galaga was the first game to be tested
(http://pici.se/pictures/abGWILvgb.jpg)
Picture is a little blured but it looks much better in reality.
(http://pici.se/pictures/MInQBMRwx.jpg)
The room lacked enough light
(http://pici.se/pictures/pYxucTJDi.jpg)
I found a new favourite game and that is Robotron 2084
(http://pici.se/pictures/ojxVEnohs.jpg)
This is the scheme for the videomod(sound not included on it) but the 75 ohms resistor was changed to a 82 ohms since I did not had any 75. It works great any way
(http://pici.se/pictures/YIrWnhTuH.jpg)
Why did you do an s-video mod since you have a CRT anyway? Here's a link to my 7800 s-video mod:
http://s1182.photobucket.com/albums/x447/jamisonia1/ (http://s1182.photobucket.com/albums/x447/jamisonia1/)
I followed this guy's mod
http://saundby.com/atari7800mod/7800_vidmod_construction.html (http://saundby.com/atari7800mod/7800_vidmod_construction.html)
I did a C-Video mod as it was the easiest way to modify the 7800 according to the guide I looked at. In the first one I saw, they used a custommade circuitboard to get the S-Video signal and I did not know of any other way to get S-Video so I took the easiest C-Video mod I could find and by help of that one, I made this guide
I might try this simplified S-Video mod in future when I get more systems