[Elecraft] Instability on 7MHz with KPA100

[Phil Wheeler]

Bob,

As I recall, there is a possibility of coupling on 40 meters from 
components in the K2 with RFC10 in the KPA100 which is located at the 
SO-239 J2.

If this is the problem, the fix is to move RFC10 as close to the top of 
the PA top panel as possible (maximize distance from the K2). 
 Apparently the cutout in the metal shield allows the coupling to occur.

73, Phil

g3pjt wrote:

>Hi
>
>I have a problem with instability on 7MHz with the 100 w amp
>
>On 7MHz in all modes the K2/100 delivers 100 + watts according to power
>meter ( external too) on some frequency which I haven't been able to find
>yet. The power control does not work.
>
>When I first start up it is OK but after a few words the K2 goes into
>oscillation.
>
>On all other bands it seems to be OK and the K2 behaves normally.
>
>If I take the KPA100 off the top of the K2 and place it alongside with all
>the leads connected the oscill does not occur and on  the whole K2 behaves
>normally on 7MHz. ( and on all of the other bands too)
>No obvious compnent problems and has worked OK until this morning
>(K2, SSB,NB,160M)
>
>Ideas?
>
>73 Bob G3PJT
>
>
>
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