Michael W. Lynch
I am going to post some pictures of the phenomenon later today. I am also going to follow up on all the suggestion or ideas presented in the preceding conversations. I have plenty to check off the list for now.
If the Astigmatism, Geometry and Y Axis Align voltages and component values check out, then I will proceed with a CRT substitution. That will definitely help to isolate the issue to either the CRT or the Instrument circuitry.
I wish that I was better at using the proper terms to describe what I am seeing. I feel like I lead people astray when I use the wrong terms or otherwise poor wording to describe the issue. For example, my using the term "loading" when this was not a case of low voltage due to an overload in the circuit.
Thanks again for all the help!