[Amps] Protecting the control grid of a tetrode

[Bill Coleman N2BC]

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