Apache grid current

[Joe Filice]

Hello all,

I'm trying to get an Apache on the air and
I think I've solved all the problems except
possibly for one.  After I initially set
the grid current to 6 mA, then apply the
plate voltage and load up the transmitter
to the recommended 250 mA, a check back
to the grid current reveals it has fallen
to about 3 mA.  I can easily increase the
drive to set this back to 6 mA.  However
if I remove the plate voltage the grid
current will soar above the 7 mA level
which the manual says never to let it
exceed "not even for an instant".  Is
this normal behavior?  Will the high
grid current on the unkeyed transmitter
damage the output tubes?  I neutralized
the amplifier as described in the manual
and got a very clear and deep null on my GD-1B
grid dip meter as I adjusted the neutralizing
stub.  The 6146s are not new, came with the
rig, and have an unknown number of hours on
them.  But I can load it up to the proper
plate current and am measuring about 110
to 120 watts out into my dummy load, which
seems reasonable considering there is about
190 watts input.  Is there any harm in just
leaving the grid current below the recommended
6 mA so that it doesn't go above 7 mA when I
unkey?  I wondered if anyone had any experience
in these matters.  Thanks for listening.

73,

Joe Filice
KQ6GL

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