[Elecraft] K2/100 current consumption problem - update

[Fraser Robertson]

Thanks Don, there is no instability apparent on a scope or spec an.  I've 
already done the R4 and RFC3 mods as per latest errata, which cured the 80m 
instability for me.  Unfortunately I'm not sure if this problem was always 
there, or started when I did the pa upgrade 
(screening/firmware/swr/R4&RFC3).

73 Fraser

>From: "W3FPR - Don Wilhelm" <w3fpr at earthlink.net>
>Reply-To: <w3fpr at arrl.net>
>To: "Fraser Robertson" <g4bjm at hotmail.com>,<gmk at gm4esd.fsworld.co.uk>
>CC: <elecraft at mailman.qth.net>
>Subject: RE: [Elecraft] K2/100 current consumption problem - update
>Date: Thu, 3 Mar 2005 19:05:23 -0500
>
>Fraser,
>
>If you have a 'scope handy, try cranking the power up to 100 watts on 160
>and 80 and observing the CW envelope - if you see what looks like weak
>modulation on the top and bottom of the envelope pattern, you have a low
>frequency oscillation.  If you do have that oscillation, the 'cure' has 
>been
>discussed on this reflector - on the KPA100, put a 1K resistor across RFC3,
>and change R4 from 100k to 39k.
>
>I have worked on KPA100s having this modulation problem, but never related
>it to current draw before, but it is worthy of investigation.
>
>73,
>Don W3FPR

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