A somewhat but not entirely rhetorical question:

At what point have you gals and guys divested yourselves of vintage tube gear for whatever reasons?  When have you decided "enough is enough" with maintenance involving costly repairs?

Congratulations @ps  in teaching yourself a valuable lesson before it was too late....
Thank you.  The key to this very happy ending was finding the local tech.  It was his extraordinary skills that kept me from making a very big mistake.  That I found him at all, was quite a stroke of good fortune.

Selling is a sign of weakness.