Made an AVmod for my 7800

[WERY]

I have modified my 7800 system so that I can connect it to an AV output. It works :D :D

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

Hope to deal with a 5200 in future

[bacteria]

Is this for the PAL version or the NTSC one? Does it work for both?

[WERY]

This is an american NTSC version. I dont know if it works for them both. It depends on the outputs where you connect to the video-signal etc. Besides the signal in an PAL 7800 might be stronger or weaker and that decides wheather you should use a certain circuit. This board I built is an amplifier to the signal for the video

I guess this mod does not work with PAL systems since the schematics claim it is for the NTSC version

[bacteria]

I have two 7800's, one is French (PAL), so RGB output (why I bought it) however other one is stock UK PAL unit so RF only. It will be weeks before I am modding the 7800 but will give your mod a go on my UK unit - if I get no result, should I try a higher or lower ohm resistors on R1, R2 or R3 to experiment?

[WERY]

Good question, I guess I can find out how it is with that and then tell you about it. Otherwise I recommend you to buy an american 7800 and do this mod as some games will not work on a PAL system. Robotron 2084 as an example

[bacteria]

...i'm rather hoping the French unit I got is RGB as stated! If that's the case, then by definition the quality of output will be higher than composite anyway.

[WERY]

The french 7800 does have RGB. On the other hand it lacks compatibility to many VCS games from what I heard and then the NTSC games. You should keep the french 7800 but perhaps sell the UK version and replace it with an american so you can play those NTSC games that are unavailable here

[Chi-kitory]

i bet a few people at acidmods.com would enjoy this. They really like it when people create pin point diagrams.
Pretty impressive mod though. Will you be making it with sound?

[WERY]

It has sound but the audio is not shown in the schematics so I just showed how to do the practical work on the audio when soldering if you look at the pictures that comes before the schematics

I might draw new schematics over this mod that looks better and show how to connect the sound