K2 Alignment and Test, Part II issues

Posted by Don Schroder on Sep 27, 2018; 12:14am
URL: http://elecraft.85.s1.nabble.com/K2-Alignment-and-Test-Part-II-issues-tp7645364.html

Hi folks,

Got to the subject location on my K2 kit #7818, and am having some difficulties with the tests. My frequency counter, when touched to the left side of trimmer capacitor C22, reads 3999.98 on the LCD. This makes me believe there is no problem with the frequency counter probe that I assembled.

On page 63, under *4 MHz Oscillator Calibration,  I selected CAL FCTR, and the LCD displays a rapidly changing frequency between 185.~ to 188.~. It does not show a frequency of 12090 kHz  suggested by the manual.  This tells me I have a problem with the PLL Reference Oscillator (since the frequency counter probe appeared to be ok). I then decided to check voltages, and discovered that I am missing some +5v signals from U4 and U5.

Any suggestions on where to look next? I’d like to trace the 5v signals, but I don’t see how to do that using the schematics. I did measure voltages on the 8 pins of the Thermistor Board, they were all 0 volts! That didn’t seem right, either.

Appreciate any suggestions! Thanks!
Don, KE0PVQ

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