[Elecraft] k2 vco alignment

Rob Gault kc2vmp at gmail.com
Sat Sep 28 16:16:54 EDT 2013


K2 #7449 VCO alignment difficulty.

Cannot get 4.0 MHz R30 voltage to change at all - it measures 7.97V.  Have
confirmed all the cap values, varicap diodes are correct parts, T5 wound
and wired correctly.

Have scoped the area comparing to a second operational K2 & the wave forms
look and behave the same as the rigs are tuned. The voltage on R30 is
simply too high at 4.0 MHz.

I set the K2 to 3.5MHz and adjusted L30 for the lowest voltage, this gave
the following results:

 3.50   4.14    4.00    7.97
 7.00   4.39    7.30    6.30
10.00   5.08   10.15    5.86
14.00   3.84   15.00    5.98
18.00   4.42   18.20    4.67
21.00   3.83   21.45    5.38
24.80   5.92   25.00    6.40
28.00   4.64   28.80    5.66    (29.70   6.87)

Should I continue the build or what else should I check?

THANKS & 73,  Rob  KC2VMP


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