My general idea was to get some functionality out of this old TV
that no one needs. If the filaments were not in serial I would not
burn them all and I would have green-blue picture.
I didnt know about that what MAGNETRON sead.
I did ask you guys should I do it but it is not your fault,
because I should have waited for the replyes.
Now I have electron gun to examine and learn about.
CRT heaters are in parallel, not series - at least in my experience, which covers all the time colour has been available in the UK. A fault you get sometimes is O/C failure of one of the heaters, which couldn't happen if they were in series.
I forgot about the two-step process of RESTORE vs. REJUVE. I had the B&K CRT tester long ago. Standard run of the mill quality device. I upgraded to the Sencore Beam Builder and what a super unit that was... even did camera tubes and prolly was the most effective brand to use on Trinitrons. But you are correct on Sony CRTs not boosting that well versus other brand CRTs.