That output is still a bit low even at 80W Martin but within reason. The
low idle current may indicate that one tube is very soft or that both are
getting tired. Try testing them individually in the amp on 40 or 80M,
there should be sufficient tuning range.
Disconnect drive from the idle one and run 40-50W input.
Altho not mentioned by you earlier, never store a 3-500Z on its side for
any length of time.
Check the filament pins of the socket for discoloration and spring grip.
Check the tube pins for sign of solder overheating, clean out and reflow
if necessary.
It is possible to have one tube operating at reduced filament voltage due
to contact resistance. This may explain the high input VSWR that went
away.
GL Carl KM1H
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