Many thanks for the input, Sean!
The clipping on top I'm guessing is where the HOT ctrl grid is being driven into conduction. There's something here we're not seeing.
If the HOT gets insufficient drive there is no HT. And the HOT goes to pieces with all that B+ and no developed grid bias. At the other extreme excessive drive can cause the output tube to be biased stone-cold, and thus not deliver the necessary output to the flyback in the doghouse--again: Insufficient HV. Just my humble theory...
This is my current thought on this matter: He's got a resistance value for plate res on his disch stage than I see called for in my scam of a similar model that shares a lot of the same stuff. Are we dealing p'raps with a typo here...? I'm still puzzling over the call for a 560K resistor where I am not used to seeing such plate res so high. And the scam I've been working from for a similar model shows a value of res of 150K. If he changes to that value I think his problems will be over. IMHO....
I've got the scams from him, and I'm giving it some thought. Lately I've been out straight, but let's see what we can do. Man! It has been so long since I've enjoyed the glory of troubleshooting an old set!
Thanks again for your input!