[Elecraft] K-1 VFO range jump

[Don Wilhelm]

Tim,

You certainly are correct in not jumping to conclusions about the need 
to just change the winding of L1 - that will not alter the tuning range, 
but will simply shift the frequency at the beginning of the range.

First check is the voltage on the VFOPOT signal line which can be 
observed at the RF Board connector P1 (to the front panel) pin 14. Move 
the VFO knob from one end to another - the voltage should change 
gradually from 0 volts at one end to near 8 volts at the other end.  If 
it does not, there is something wrong with the VFO pot or the 
connections to it.

If you do get the expected voltage range, check for the same voltage 
range at the cathode of D3 (or pin 2 of RP2 (both should be the same 
because they are connected).

If all is well so far, then suspect that the problem has to do with 
soldering.  Reflow the soldering at C2, D3, RP2 and possibly other 
points with a hot iron (750 degF).

73,
Don W3FPR


On 6/24/2012 5:32 PM, k3hx at juno.com wrote:
> My K-1 quit (no TX, no RX) a few months ago and am just now getting
> around to working on it.
>
> It is a 2-band kit with 20 and 40 installed.
>
> Originally set up for 7.000- at 7.060; 14.000- at 14.060.
>
> I removed and replaced the filter board.  RX, TX fine except the
> range is now 14.047.3 - 14.075.1 and 7.053.6 - 7.081.3.
>
> Spread the turns of L1 and could get to go as low as 7.0361 and as high as 7.0640.
>
> These frequencies agree with a good receiver and a good signal source.
>
> I'm reluctant to snip off a turn from L1 since it worked fine before
> with the current number of turns.
>
> A concern is the lack of tuning range.
>
> VFO OSC is 3.027 - 3.055.
>
>