Here are a few books that I've found useful:
Basic Television Principles & Servicing, Bernard Grob
Elements of Television Servicing, Marcus & Gendler
Mandl's Television Servicing, Mandl
Popular authors like Marcus or Grob had books that went through multiple editions. Mine are from the mid-1950s. If you find an edition published a few years after the TV you're working on, it will mention common problems of the time or with particular models, etc. There are a couple more kicking around here somewhere . . . a Coyne book and at least one other.
It's nice to have a handful of books, since each will have somewhat different approach & coverage. For instance, the Mandl book is not my favorite overall, but it has the most detailed explanation of Barkhausen oscillations.
I have the 1957 Pict-O-Guide for color TV and it's a great piece of writing. Doesn't cover everything, but no book does. My other color TV books are mostly solid state and I can't recommend one in particular.
These books typically sell cheap thru used booksellers, Amazon, eBay, etc. Not much demand for tube TV repair books these days
Phil Nelson