[Elecraft] Haunted K2
Tom Hammond
n0ss at earthlink.net
Wed Jan 4 12:09:50 EST 2006
Hi Dave:
This is probably doe to the fact that the brass counterweight inside
the back of the VFO tuning knob is just a slight bit eccentric with
regard to weight... just about all K2 VFO knobs will demonstrate this
'quality' of there's insufficient rotational resistance applied to
the back side of the knob.
Add a small bit more 'resistance' to the knob tension via the felt
pad which SHOULD reside between the knob and the front panel.
I've found the easiest way to mete-out tiny amounts of rotational
resistance is to completely loosen one of the two VFO knob setscrews,
and then to loosen the 2nd one and to re-tighten it JUST to the point
that it will keep the knob from pulling off the encoder shaft. THEN,
with the butt end of a small screwdriver, I'll 'tap' on the center of
the VFO knob, pushing the knob in toward the front panel and checking
rotational resistance following each 'tap'. Once I get the resistance
where I want it, I'll first tighten the 'snugged' setscrew and then
the loose one.
Done.
At 08:39 AM 1/4/2006, you wrote:
>If this is a duplicate, I appologize, but I posted it 18 hours ago
>and it hasn't appeared. Is there some delay built into this relector??
>
>
>
>Good afternoon,
>
>Now that I have your attention, I don't really think that my K2 is
>haunted, but it does seem to want to tune itself.
>
>As I tune the knob up and down the bands and come to the frequency that
>I want to listen or transmit on, I stop turning the knob and I take my
>hand off. The knob is fully stopped when I do this. As I watch the
>readout after taking my hand off, the frequency starts to change slowly,
>sometimes adding (or subtracting) as much as 80 hz to the frequency at
>which I stopped the knob. The knob is actually turning by itself. It
>may go either direction and seems not to be correlated to whichever
>direction of rotation I was using when I stopped turning.
>
>I have been using the K2 regularly on the HF bands only for the past few
>weeks. Since building the unit last spring, I have used it mainly as an
>IF rig on the microwave bands. Until the last day or two, I haven't
>noticed the "self tuning" feature.
>
>Perhaps this phenominom has been previously noted and a fix found. I
>cheerfully admit that I haven't done any research in the Elecraft Archives.
>
>So....what say ye about this?
>
>Dave, K4TO
>
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