I have the same problem here the last tech retired last year , and he was not interested in tubes that much , I always get told , " why do you want to fix that , its B&W and it old ?" All I tell them is , " Thats the whole point or my collection " .
Audiokarma is a great place , I really enjoy discussing old tv's and doing what I can to help out a fellow collector .
I ran into a previous thread from 2004 , since then have you changed the electolytics ? and the 5U4 ?
If you want to leave the cans , there is a great unit for testing them .
A Heathkit capacitor checker ,the C-3 is a great unit and will test for leakage using a voltage source it suppies to the cap at the proper working voltage .then it determines if the cap is leaking or not ,plus it has a resistor checker in it also , it uses a magic eye . They sell for 35 buck usually .
It would pick out problem parts in a hurry .
I have the sencore LC2 leakage checker and I dont know how I lived without it .
It's the best $ 28.00 I ever spent .
I will go throught the schematics that I have and see what I can find that is perhaps powering the vertical , and also the sound circuit .
Good luck with the diode .
