[Elecraft] RF POT (K2)

[David A. Belsley]

Fred:
   I had this problem with s/n 744.  A postmortem showed that the 
plastic shaft inside was breaking apart into little pieces that would 
get behind the wiper, making contact problematic.  I think the cause 
was excessive play in the shaft, noted by its being able to be moved 
sideways significantly.  Normal side pressures during usage were 
causing the shaft to grind apart against the bushing housing.

   I replaced the pot.  It is not that bad a job.  And then I added a 
nylon washer between the knob and the panel to relieve the possibility 
of damaging side pressure.  I put these washers behind all the smaller 
knobs.  I found some black nylon washers that had exactly the right 
inside and outside diameters so that they look just like part of the 
knob.  I found them at my local hardware store, but I don't know how 
universally available they are.  They are made by Hillman Co. of 
Cincinnati, OH, and are their part number 58059-N.  The ID is .257", OD 
is .5", and the thickness is .062".   Once in place, with the knob 
snugged up just enough to allow free (non binding) turning through the 
entire range, there is hardly any noticeable sideward motion to the 
knobs.  I haven't had a problem since (knock on wood).

best wishes,

dave belsley, w1euy

On Jun 19, 2004, at 11:31 AM, Indy wrote:

> My audio cuts out momentarily whenever I rotate the RF gain pot.  I 
> suppose the RF gain pot is generating noise (dirty) and that noise is 
> triggering the AGC.  I do find that if I rapidly rotate the knob back 
> and forth through perhaps ninety degrees a dozen times or more, the 
> problem is temporarily reduced.
>
> 1)  Do others have this problem?
>
> 2)  what is the recommended solution?
>
> I have never done the AF pot mod because it is not noisy at all.
>
> tnx,
>
> fred
> kt5x
> K2 # 0700
> Palm # 0070
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