Michael W. Lynch
I have restored several of this family of scopes. Finding OEM style caps that are good is not a really viable option.
I use Modern radial lead caps and these adapters:
I would say that you have issues with you -15 and -8V Supply. Caps may help rectify some of those issues. A Good place to start in any case. Get you supplies back in spec and you will go a long way to fixing the scope.