Yes, you absolutely would get a signal if you bet a cap between the scope probe and the circuit you are probing. That's the same as putting your scope in AC coupling mode.
"I grounded the scope input by attaching the scope input to the same point."
I don't understand that statement. You should not be grounding the scope input. I think be are mixing up terms here.
The scope PROBE should always be grounded. That's the black clip. It goes to the chassis. The scope probe tip goes to the test point.
You don't need a 1,000 pF cap anywhere for anything.
You wrote "I have the scope probe grounded through a 1000pF capacitor". That would mean the black clip on the scope probe would be connect to one end of a cap and the other end of the cap would be going to the chassis.
That is not what you show in the picture.
The scope trace should look better than that. Unless it's your camera making it look faint and smeared.
Here's an "S" curve from a similar chassis on a 350MHz bandwidth analog scope with no bandwidth filtering.
