I wanted to use the 4050 and as much as possible from the vcs-board but without destroying it!
I found some schematics in the web and I took a look at the Atari 800 and 800XL schematics.
After comparing all I built a prototype on a small breadboard.
I watched the result on my Sony broadcast monitor, the 1702 and my 1084s.
I also looked at my scope and compared to a C64-luma and chroma signal.
After optimization here is the final schematic:
I lifted the input pin of six resistors on the board and soldered wires in the open hole to grab the signals. I connected two wires to unused holes with +5V and ground.
It sadly was not possible to use the lum-resistors because they are too big for a bright picture. I built a luminance circuit similar to the Atari 800 - and it works perfectly.
I build a chroma circuit similar to TePe's mod but I leave the input cap away - there's already a cap on the vcs-board.
The audio-signal from the vcs is so strong - no amplification needed! A cap is on the board and I added just a 10k for protection and to reduce the output a little bit.
Prototype:
Finished and fully connected board:
It is so small that it fits above the vcs-board in the aluminium-box!
I lay the svideo cable at the side of the vcs-board to the solder side and through the hole for the adjustable inductance (not needed anymore ;) ).
On the scope you see above the luminance signal with the syncs (200mV/cm) - about 500mV - below is the chroma signal (I forgot the scale).
Both are similar to a classic C64 s-output and should work at any monitor / TV.
Sample-pictures from my 1702 - it is my favorite svideo-monitor - much better than any 1084 philips or daewoo! Only the 1081 or 1902 have a similar good picture!
