K2ATOBKT question

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K2ATOBKT question

n6wg
I've just started the A to B upgrade, and I'm still on page 5, doing the
Modifications to Cure Instability at the bottom left corner of the page.
The first step is to be sure that C70 and C71 in the VCO area have the
shortest possible leads.  Then the last step in that segment is to
remove C70.  This seems strange.  Is this the same VCO C70 that we just
snugged down in the first step?
I'd like a reality check here before I go on.
Thanks and 73
Bob N6WG

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RE: K2ATOBKT question

Sverre Holm

-----Original Message-----
The first step is to be sure that C70 and C71 in the VCO area have the
shortest possible leads.  Then the last step in that segment is to remove
C70.  This seems strange.  Is this the same VCO C70 that we just snugged
down in the first step?
-----
The application note on http://www.elecraft.com/Apps/Alert11_WAOF.html sheds
some light on it. It says

"C70 needs to have short leads and should be positioned close to D22. If
necessary, remove C70 and scrape some of the ceramic coating from the leads
of the cap so it can be installed very close to the PCB."

Also, on rereading the A-B mod document, it really says "Try them in order,
and stop when the symptom disappears." So the removal of C70 is only a last
resort and is not necessarily required, it all depends on whether you have
any instability left on 7185 kHz.

73

Sverre
LA3ZA
http://www.qsl.net/la3za/
 



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