Atari 7800 s-video mod (with pics)

jamisonia · August 12, 2011

First post and its my Atari 7800 modified to put out crystal clean s-video. I started by using this guide:

http://atari7800.org/7800mod/7800_mod.htm

However I find using this resistor ladder results in a very dark picture for 7800 games, and a virtually black picture for 2600 games. I had this experience on two different Atari 7800s. So I decided to change to the Saundby mod described here:

http://saundby.com/atari7800mod/7800_vidmod_construction.html

and found this to work very well for both types of games. After speaking with Mark over at Saundby about my issues using the other mod, which is supposed to us Atari's own resistor ladder, he told me he had the same results when modding his 7800, which is why he developed his ladder with a 10K pot.

I find this to be the case in my experience, and I would highly suggest anybody attempting to modify a 7800 for s-video to consider using the saundby mod, or making a further attempt to ascertain exact resistor ladder values, lower than the Atari resistor ladder, so that they wouldn't have to use the 10K pot in the Saundby mod. I wonder if these might also apply to 2600 and 5200 s-video mods.

If anybody here wants to do this mod, and wants or needs some help, please pm me.

For your viewing pleasure I have included some pictures. Xevious is the best picture to tell the difference. Look at the dark bushes. With RF they are very blurry. With s-video you can see blue dots that did not exist in the RF picture.

Please see my photobucket album for all the pictures I took associated with this mod

http://s1182.photobucket.com/albums/x447/jamisonia1/

Edited August 12, 2011 by jamisonia

gorfcadet · August 12, 2011

Nice results. I'm glad mine is modded and ready for my XM.

Thanks for sharing! Future proofing the Atari is a worthy cause indeed!

Now if anyone is ready to come up with an hdmi mod... I know there isn't a point visually, but svid is getting rare and composite is very substandard. Comp looks worse than coax on one of my lcds! Composite results definitely vary by tv aparently... same system - two tvs - very different results.