The following design is a way to connect the atari video port to a commodore 1084s monitor. For some strange reason the C= monitor refuses to cooperate with the composite signal from the atari. However if you connect the horizontal sync pin of the atari to the composite sync input of the monitor and the vertical sync from the atari to the vertical sync input of the monitor everything works flawlessly.

It's also worth noting that the composite signal works perfectly when connected to the CVBS port on the 1084s monitor.

picture 1. Schematics. Ports shown facing the user.

Thanks for your info. The pin 8 of D-sub is true the horiz.sync., but for connection with my Atari 1040 ste is not work, its scrumbled. The only way, is to feed the pin 7 in monitor (who is composite sync. input) with the atari horiz. sync. outpout to work like a charm. Unbelievable or not, but  this work perfect!