Could not repeat while monitoring the HT.
So as I can't believe an electrode or 2 failure,or whatever, in the GZ34
had cured itself by my external and internal heating, just a coincidence
and some other problem?
With original failure returning immediately to full volume, without
cooling down, might suggest a "cured" internal problem.
I tried heating the pcb with hot air and no return to failure mode.
So valve test the GZ and the other valves, put a saggy SS dual rect in
there after checking the GZ valve base. Some heavy prolonged testing and
return to owner with fingers crossed?