[Elecraft] [K1] VFO Drift Problem

[Jessie Oberreuter]

      IIRC there are two cascaded voltage regulators before the VFO which 
may also be good candidates for improvement.  Mine's been more drifty 
since I blew the first one; I probably should have replaced the second one 
at the same time.


On Wed, 4 May 2011, Matt Scholz wrote:

> Hi -
>
> I am trying to reduce my K1's VFO drift to an acceptable level. The VFO
> frequency drifts up at a rate of about 30Hz/minute (after a 5 minute warm
> up). Even after one hour, the drift is still about 15Hz/minute. This is
> too much, obviously.
>
> I have been trouble shooting this with the help of Gary, AB7MY. So far I
> have done the following:
>
> * Removed C2 to isolate D3 from the rest of the VFO circuit. No change.
> * Replaced all three VFO poly caps (one at a time). See above.
>
> I was wondering if anybody had any ideas on how to further trouble-shoot
> and resolve this issue...
>
> Thanks in advance and 73,
>
> -Matt / W6ZBA
>
> K1 #2978
>
>
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