4MHz Oscillator Calibration

[David Haas-2]

My frequency counter probe gives me erratic readings during the 4MHz oscillator calibration.  However if I physically hold the 10pF capacitor during the test the readings settle down much nearer the frequency of 12090 kHz +/- 30 kHz as described in the owners manual.  Can I consider the test in range?

Dave N1PT
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[Jim Younce]

<<<My frequency counter probe gives me erratic readings during the 4MHz
oscillator calibration.  However if I physically hold the 10pF capacitor
during the test the readings settle down much nearer the frequency of 12090
kHz +/- 30 kHz as described in the owners manual.  Can I consider the test
in range?

Dave N1PT>>>


If this is a new K2 check Q9 and 10 on the control board.  If they have blue
paint on the flat side of the transistors you need to call Elecraft and they
will replace them for you.  They received a bad lot of MPS5179 transistors.
They work but their gain at the operating frequency is too low to drive the
input of the frequency counter.

73
Jim Younce  K4ZM


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[Don Wilhelm-3]

Dave,

Although the PLL may be in range, you should have a steady reading without
holding anything.  Check the probe --
First look at Q9 and Q10 on the Control Board.  If the flat faces are blue,
the 2N5179s are suspect and you should request new ones from Elecraft.  If
the 2N5179s have black faces, then check your probe carefully for bad solder
connections - also check that the probe plugs into the Control Board the
right way 'round - the shield should be located closest to the side panel.

OK, I have no more suggestions until I have more information.

73,
Don W3FPR

----- Original Message -----

My frequency counter probe gives me erratic readings during the 4MHz
oscillator calibration.  However if I physically hold the 10pF capacitor
during the test the readings settle down much nearer the frequency of 12090
kHz +/- 30 kHz as described in the owners manual.  Can I consider the test
in range?



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