Thank you all for the direction on looking at the capacitors. Sorry for the delay in my reply. I have not gotten the chance to look at the scope since doing the tube-removal checks a few days ago.
I had checked the capacitors C611 and C612 previously, as they were suspected to be an issue early on (but both checked out okay with the resistance test), but I never checked any of the others in the power circuit.
I can check the C682 and C684 later tonight or tomorrow, based on the instructions from Trevor. Unfortunately, I do not have a capacitance meter available for use, but I have gotten in my probes for the analog meter, so I can check the caps with both the DMM and analog meter, and then report in my findings. I also got in more silver-bearing solder, so removing any components to get the readings won't be an issue.
I recall from earlier postings that the non-ceramic capacitors are prone to failure in the older scopes, so are there any other capacitors that I should check as well for potential failure? (there appear to be quite a few other EMC/PTM capacitors in the scope, based on the manual)