[DaveWM]

test point D on the set, its on a term strip, if you are lucky you will see a paper tag on it, or it may be stamped into the top of the chassis IIRC. its not a wire on the tuner, its after all the IF stages, then there is a diode (which could also cause the issue but I doubt it).

I assume not only are the tubes good in the tuner but they are lighting up and getting B+ as well?

the cap will block any DC from the set, there should not be any, but it just in case you inadvertantly touch a B+ it will save your DVD. Aways a good idea to check the TP with a multimeter to check for DC before connecting anything up.

opps hold up, wrong zenith, I will have to check to see if that D is still the right test point

well not sure I did not have that schematic I have a 25NC38 and a 24MC32. You need to get a schematic for that, one of the video detector output test points will be indicated. that is the composite signal. done expect it to be a great pic, the PP is prob not going to be the same, but you will at least see something.

the other way to check would be just to scope it if you have a scope.