[Elecraft] K2 160m VFO problem

[W3FPR - Don Wilhelm]

Ray,

You may have a situation with a PLL range that is a bit on the narrow side.
You could try shifting the entire VCO range (adjust L30 while observing the
voltage on R30) to see if you can get the 160 meter band within range too -
I would try that first.

If the above fails, you can adjust the value of C75 a bit at a time until
the voltage at R30 comes into line.  I believe you should reduce the value
(someone correct me if my thinking is backwards here).

73,
Don W3FPR

> -----Original Message-----
>
> I've just installed the 160m option to my (second) K2. However, the VFO
> refuses to work, The problem sems to be in the PLL / VCO area.
> Monitoring TP1 shows no ouput on 160, all other bands OK. Reference
> oscillator at TP3 is fine on 160 and tunes perfectly.
>
>
> As far as I can see in the PLL / VCO area, the only component that is
> excusively used on 160 is C75. I know from experience of my first K2,
> that if C75 becomes O/C, the oscillator range changes but continues to
> work. However, I changed C75 (twice) in any case but to no avail. The
> relays are OK, I can see that when K13 is reset (for 160) I get
> continuity up to T5. D21 / 22 seem to be OK. If I measure the VCO
> control voltage at R30, I get +8V which changes if I tune but goes
> immediately back to 8V.
>
> Can there be any other cause than C75 / relays?
>
>
>
> 73 de Ray / SM0XLP
>
--
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.344 / Virus Database: 267.11.3/106 - Release Date: 9/19/2005