I would start by measuring the RFC's at the grid pin of each tube. If one
is open, or the pi's slammed together there was a short in that tube.
Also check the bias zener, it is located on a small bracket bolted to the
bottom of the filament xfmr. When that shorts it often takes the small
electrolytic on the terminal strip right next to the zener.
When this happens it often takes out the 100VDC supply which may take out
the filament/bias xfmr if you keep it on too long. There is a decided
domino effect with the 922.
Next, power up with both tubes removed...making sure there are no
fireworks, etc.
Install one tube at a time, looking for unwanted plate or grid current.
If all is OK, close the relay line and look for some idle current; about
50ma in CW position.
Then install the other tube (still one at a time and repeat the above
steps).
Finally fit both tubes, check for idle current and slowly apply drive.
Once you get the amp home, private E-Mail me and I will recommend some
other simple changes for reliability.
73...Carl KM1H
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