[Elecraft] K2 VCO Alignment only 0.02V @ R30

[Don Wilhelm]

Jeremy,

Do I recall correctly that you had a good PLL range?  If so, I have 
trouble believing there would be 300k resistance from CB U6 pin 24 to RF 
U7 pin 2 while you have zero ohms to U4 pin 5.  Are you certain you 
counted the pins correctly?  Pin 1 has a circular solder pad and the 
rest are rectangular.

If you want to check the operation of RF board U7, monitor the DC 
voltage at pin 7 while rotating the VFO knob - the voltage should change 
gradually while tuning through a 10 kHz range and then jump back to its 
lowest (or highest depending on which way you rotate the knob) at the 
end of each 10 kHz interval.

Did you remove the Control Board when you made the measurement on the 
collector of Q1?  If not, then somewhere in the vicinity of 5 k is not 
unreasonable.

73,
Don W3FPR

On 2/3/2013 12:41 PM, JeremyJones wrote:
> Looking over the board I did find that I had U8 C45 connected to pin7 instead
> of pin6.  That has been corrected.
>
> U6 pin 24 to U4 pin5 is less than 1 ohm, however U6 pin24 to U7 pin2 is 300k
> ohm.  I don't see any damage on the board.
>
> I also noticed going back to the beginning for the resistance checks on the
> control board that Q1 collector should be great than 1M, but is reading 5k.
>
>
>
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