Others' opinions may vary, but here's my $.02 worth..
1. Service-wise, those early printed circuit layouts were the worst ever conceived, with the foil side of the boards made inaccessable
(what were they smokin' to come up with that idea?
Musta thought the design was bulletproof and would never need troubleshooting.
2. The newly-introduced small neck CRTs usually died an early death. Before proceeding any further, find someone with a CRT tester to verify that (if by some miracle) the CRT is good.