For future reference you can look up most TVs service info here:
https://www.samswebsite.com/ Don't buy it there unless you can't find an original paper copy elsewhere....The website sells low quality scans and or photocopies of the literature for usually 4X what a good original copy goes for on eBay, etc...Why pay more for less legibility. IIRC the radiohistory website that has a large magazine archive has a Beitmans most often needed for free...Beitmans is less comprehensive than Sam's but fine for common sets.
CRTs are obtainable used and sometimes NOS. Your set uses a old measure CRT. In 1968 the us federal government passed a bill to force CRT makers to change their size designation from bulb diagonal to viewable area diagonal so a 1966 25XP22 would be made in 1969 as a 23VXP22. Delta Gun console CRTs pretty much were all interchangable as long as the screen was the same size. So any 25" non-V type or any 23V CRT should fit and work. Undesirable common/cheap1970s solid state consoles like Zenith Chromacolor IIs and RCA XL-100s (that name stuck around well past the 70s into inline gun CRT era) are a great, often free for the asking, source of replacement tubes for older consoles. In 1970 Zenith introduced the Chromacolor Black-Matrix CRT which was along with the Trinitron one of the 2 advancements that transitioned CRTs from 50s tech to 80s tech....Black matrix tubes will noticably improve picture quality and are a worth while upgrade on 60s sets. Zenith Chromacolor tubes tend to be the most immortal color tubes out there...most still test like new and the weak ones still seem to produce a much brighter picture than they have any right to for any given tester reading.