Thanks everyone for the help so far. I now have the scope connected in X Y mode direct to the B&K 415 and get a signal, see the below image. Further I have the direct probe connecting the B&K 415 to the Video detector (test point C1). The issue now is I get no feedback from the TV, whether connected to the TV or not I get the same curve on the scope.
Do I still use the Zenith service manual directions? I did try to connect the RF-IF-Video output and feed it into test point G as per the service manual but no change.
Could something be wrong with the B&K 415?
