[Elecraft] K2 curious problems

[Don Wilhelm]

Bill,

#1 - the K2 A=B button is working as designed - the VFOs do not track 
each other, they are independent.  This is normally the first thing one 
would do when setting up split on the K2 - set the VFOs equal, then move 
your transmit VFO up to where you wish to transmit and activate SPLIT.

#2 - It is difficult to say where the distortion is coming from without 
further investigation.  That is not normal.  One thing I might mention 
is the possibility of hum from an AC transformer being coupled into the 
K2 VFO.  Try moving the K2 at least 2 feet (more if possible) away from 
anything on the desk containing a transformer - some desk lamps contain 
a transformer in the base.  Should a nearby transformer (or other form 
of magnetic coupling) be the source of the distortion, and you have to 
place the device near the K2, Elecraft has a VFOSHLDKT mod kit available 
that can be added if needed.

If the distortion is not caused by a magnetically coupled field, you 
will have to do some testing to find the source.  I would suggest 
connecting the output of the product detector (available at the J5 
location on the RF Board) to an external audio amplifier or computer 
soundcard input to see if the distortion is present there.

If you have the KDSP2 option installed, try putting it into BYPASS to 
see if the distortion stops.  It is possible to make the KDSP2 noise 
reduction so aggressive that it begins to distort.  If that is the 
cause, turn off the NR and NT settings in the DSP menu or set the 
parameters back to the defaults (see the KDSP2 manual for instructions)

73,
Don W3FPR

On 2/11/2015 12:23 PM, William Schmidt wrote:
> I'm looking for some help with my K2 (SN 5165) that has developed the following problems:
>
> 1.  Even after pushing the A=B vfo control, B does not track with the A vfo but remains where it was when the A=B was pushed.
>
> 2.  When I turn on the K2 the audio initially sounds fine but after a variable interval it becomes distorted and muffled.  The strange thing is that if I cycle the power off and on the audio returns to normal.  This doesn't affect the transmitter.
>
> The voltages on the 5v and 8v lines measure ok.  I'm not sure if this is a problem with the MCU or with a relay that needs to reset.  Is this a problem that others have noticed?  I'm at a loss as to how to track this down.
>
>
>