IN NEED OF HELP s-video + GMA

So i have a rig in in the air, And s-video running up to the DL2 that i have in the air. I go to my console and try to switch to the S video and nothing happens the graphic eng stays in. I thought maybe i was missing S-video to the DL so i put a monitor on the other end of the S cable and saw signal. Im not sure what im doing wrong. Please HELP!!