LittleJoe

flammingcowz, on Tue May 8, 2012 7:27 PM, said:

No, it doesn't. If you lift pins 6 and 9 you do not have to remove the resistor below the TIA. You need not remove the other components as well. The only reason for removing the components on the board is to disconnect pins 6 and 9 from the rest of the circuit on the Atari. The audio pins 12 and 13 need to be lifted as well.

I was never 100% happy with the composite output, it never looked as nice as the rock solid s-video. I could see the TV I was using automatically adjusting the brightness as I turned the pots, and for a split second I 'd have excellent composite video, but then the TV would adjust making it too bright and washed out, and was forced to adjust the brightness down on the TV. This would reveal color clock skips in blues and other colors in composite, whereas s-video would be fine. Intuition told me that the sync signal was a little strong compared to chroma/luma, going into the fms6400 filter.

So I've made a small change the recent builds that I've done. I've substituted a 1.6K resistor in place of R3 which was 1.0k ohm. I also put 75 ohm output resistors on the composite, chroma and luma jacks per the applications notes for the FMS6400. Not really sure if the location makes a difference, but they appear to be right on the jacks in the application notes. Are they located there to reduce RF interference? The output resistors on Chroma and Luma aren't really needed, as far as I can tell, but installing them allows a single adjustment for Composite and S-Video.

The best way I know how to get rid of the 7800 mode diagonal interfence is to cut the wire (install a manual swtich) from the TIA 9 connection to the mod board. Disconnect it temporarily and give it a try.

Nope. NTSC. Corrected that. Thanks.

snstay, on Wed Sep 28, 2011 7:22 PM, said:

http://www.atariage....d/page__st__125

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