Let me start this over.
Typically it is imperative to not apply drive to a grid driven tetrode unless
anode voltage is applied. This is usually accomplished by interlocking the T/R
switching.
I have a Harris RF-110A which uses a pair of 8122s. When operating, the 8122s
are Class A. However there is no protection against applying grid drive at any
time (power on / power off / anode on / anode off / filament on / filament off)
- the input is completely unswitched.
Simple question: Will application of 20 or 30mW of RF damage the tubes when
they are not "ready" ?? It looks like the 8122s can handle a couple watts of
grid dissipation each - is this relevant if they are driven when not "ready" ?
I can add a drive interlock if necessary - it's going to be a pain - though not
as much pain as toasting the tubes.
Thanks, Bill
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Bill Coleman N2BC
http://home.stny.rr.com/n2bc
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