Hi Joseph Daniel, Hi everybody,
The problem when creating a composite input on the grid of the video output tube is that there is insufficient gain to produce a bright & well-constrasted picture.
French TV collector Pierre Genet therefore developed a composite input buffer amp with adjustable gain + black level control for this specific purpose. The device adds a standard 75 Ohm 1V peak-to-peak composite input to any vintage TV. See the circuit on his site:
http://www.cfp-radio.com/ - site Home
then navigate to "Realisations"
Pass the radio stuff (TSF) & scroll down to the TV section. Click on:
"Preamplificateur video pour anciens televiseurs monochromes"
circuit schematic, parts list & PCB layout in pdf files.
No IC's just two standard transistors.
TV screen shots of with/without the preamp to show its effect.
If you use the circuit, please drop a line to thank Pierre.
Merry Christmas to all !
jhalphen
Paris/France