Dear Wilford, bravo for your work, very sorry for the problems ....but an old story.
Such vintage scopes are 1970s..1980s ( check serial, parts date codes). So, common that insulation, transformers high voltage are going to fail.
Our workhorse scopes since 1970s and still have a few ....Unless it was dropped or shipped roughly, the CRT is unlikely to fail, but does suffer gradually losses of cathode output
Most likely fail points...
1/ High Voltage multiplier, HV transformers
( many threads on rebuild, DIY)
2/ arcs, corona due to deterioration of cables, insulation, dust, carbon deposits over the decades at CRT Ultor to Aquadag.
3/ power supply electrolytic capacitors
thus complete restoration of 465/475/B is a project. And after you still have an old and tired scope.
Nowadays we use the 1980s..1990s Tektronix CRT Like 2465/7/B or 2236 etc.
Suggest you search both tekscopes and tekscopes2 on groups.io as well as EEVblog and general net for Tek or Tektronix 465 and 475
restoration, repair, high voltage teardown
Maybe consider to get another scope.... last version 475B was superior in several ways...look out for them at ham radio flea, Craig List, or epay....
Bon chance
Jon
Jean-Paul