[Amps] sb-220 non uniform grid current ??

[R.Measures]

With 700 - 800mA key-down on the CW tap, what is the grid-I?  Tnx.  

>All,
>
>I have an sb-220 with non-uniform grid current. With low to medium drive 
>grid current is linear (or apparently close to it) with plate current 
>(minus about 100 ma base) and output power. However if input drive 
>exceeds the medium level of 25 to 30 watts grid current starts to hockey 
>stick "high". It is not a digital switch; but a very steep response.
>
>The components in the bias and grid meter side of the circuit have been 
>checked in circuit. The grid bias coil has been replaced with an 1/8 
>watt 33 Ohm resister.
>
>Thanks,
>Dan
>
>
>
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