[mikethedruid]

If you are planning to read some good books covering the repair of tube type radios, I suggest these:

Audel's Radioman's Guide by Edwin P. Anderson, preferably one of the 1950s editions. 
https://www.amazon.com/Radiomans-Constru...oks&sr=1-2

Elements Of Radio Servicing by Marcus and Levy, a more detailed work on the circuitry used in tube radios. I really like this work because it covers all the theory you NEED, but does so in a clear, concise manner and does not go off into the weeds. I highly recommend buying a hard copy of the book, but it is also available as a PDF online
https://www.amazon.com/Elements-Radio-Se...oks&sr=1-4

https://worldradiohistory.com/BOOKSHELF-...y-1947.pdf

Once you have read these, you will have a good grasp of the basics you need. Be sure to learn all the basic symbols used in the schematic diagrams. That is essential.

And last I'll recommend the very first hard cover book I bought on radio and electronics back when I was about 10 years old, The Complete Book Of Radio by Raymond Francis Yates and Louis Pacent. It was published in 1922, and covers the early development of radio and the theory at the time. The information in it, although very early, is still relevant and valuable. Here is a link to an archive site where you can download an online version...
https://archive.org/details/TheCompleteRadioBook

Have fun ! You're on a new adventure and quest for knowledge.