s/n 5567 Alignment and Test Part II problems

[McMillan, Terry]

Good evening everyone,



I have just completed RF assembly part II and started the alignment and test when right off the bat I have a problem.



The "4 MHz Oscillator Calibration" step 3 on page 60 states "the counter should show a frequency of 12090 kHz +/- 30 kHz".  Well mine reads 12600.  Searching the archive I found plenty of examples of the PLL reference oscillator range test but nothing about not getting the wrong reading.  I checked the freq probe by testing and finding 4000.00 at C22.



Any suggestions on where to start troubleshooting.



Thanks



Terry

VA6MAC

K2 s/n 5567



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[Don Wilhelm-3]

Terry,

You do have a problem.  First thing to do is check the soldering carefully,
then re-check the soldering.  When you have finished that, check the
soldering.  That is the most common failure.  The second most common failure
is components finding their way into the wrong holes.

To narrow your search in this particular case, open the schematic to the RF
Board sheet 1 of 4 and find the components shown in the upper left area -
marked 'PLL Reference Oscillator'.  You will likely find the source of your
problem among those components - include the thermistor board (and the
soldering on the back of it) in that list of suspects.

Don't be concerned about the 4 MHz reference oscillator right now - just set
C22 to the center position as indicated in the manual.  After you complete
the K2 and have everything working, you can take steps to set the reference
accurately.  The internal check you did says nothing about the accuracy of
the 4 MHz oscillator - it only tells you that the counter is working.

73,
Don W3FPR

> -----Original Message-----
>
>
> I have just completed RF assembly part II and started the
> alignment and test when right off the bat I have a problem.
>
>
> The "4 MHz Oscillator Calibration" step 3 on page 60 states "the
> counter should show a frequency of 12090 kHz +/- 30 kHz".  Well
> mine reads 12600.  Searching the archive I found plenty of
> examples of the PLL reference oscillator range test but nothing
> about not getting the wrong reading.  I checked the freq probe by
> testing and finding 4000.00 at C22.
>
>
> Any suggestions on where to start troubleshooting.
>
>

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