I don't know if anyone is interested or not but i figure this will
still be good for the archives if someone else has the problem in the
future.

It turned out to be the vertical output amp after all. I tried
swapping them again and this time it worked perfectly! I must have
made a mistake the first time. Anyway, thank you all who responded to
help me out as I'm extremely happy that I got this thing going again
(and got use out of the broken 465b that was collecting dust!!)

On top of all that I learned a great deal about the workings of my
scope.

Thanks!
aaron