[Elecraft] K2 VCO Alignment only 0.02V @ R30

[Don Wilhelm]

Jeremy,

OK, let's back up to U4 and U6 for a bit.  Set the K2 to 7100 kHz and 
tell me the voltages at U4 pin 13. U6 pin 6 and U6 pin 7.
You can remove the bridge between L30 and T5.

Also lift one lead of the red winding on T5 and check the resistance 
across L30.  In the row of 3 pins, resistance between the leftmost pin 
and the rightmost pin.

Technical talk - L30 and the red winding of T5 should result in a lesser 
inductance than either of them alone.  It appears as though you have 
only T5 in the circuit.  An open winding at L30 would make the frequency 
too low - your present condition.
The reason for the request of the DC voltages at U4 and U6 is to 
determine if U6 is operating as expected and there is the expected drops 
between U4 pin 13 and U6 pin 6.

73,
Don W3FPR

On 2/2/2013 5:46 PM, JeremyJones wrote:
> Don,
>
> Checked D19 is n in the secondary menu.  L30 does change frequency.
> Soldering iron is set to 775F.  I'm using one of those illuminated workbench
> magnifying lamps to examine my work.  Even still I reflowed the solder on
> all joints to be sure.  U6 circuit components are the correct values and
> orientation.  U6 pin 5 reads 4V.  Bridged the pins between L30 and T5 and
> resistance is 0.  Checked before bridging and it was as well, but wanted to
> be sure.
>
> I am at a loss..
>
> Jeremy
>
>
>
> --
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