[Elecraft] Freqency Display K-2

[Sean Baxter]

I had a similar problem.  I found that I had blown Q9 and/or Q10 MPS5179's.
Replaced them and all works well.
Sean - K3XT
#2311

----- Original Message -----
From: <hemiller@toast.net>
To: <elecraft@mailman.qth.net>
Sent: Monday, January 21, 2002 11:00 AM
Subject: [Elecraft] Freqency Display K-2


If this already made it to the list, my apologies.  I sent a copy from my
work QTH, and according to the e-mail FAQs, it was probably blocked bcause
my work QTH e-mail address is not suscribed to the list.  Hence, this post.
;>)

Hi,

was wondering if anyone has come across this problem:

I finished the alignment part 1of the K-2 procedures, and preceded to build
up the RF board as instructed.  All tests in alignment one went perfectly,
including the rf probe check.  I finished the RF board up to alignment part
2, and double checked everything (that doesn't absolutely guarantee mistake
free, but it helps).  When I applied power to the rig, everything went as
expected (no errors, smoke...etc).  I attached the probe to TP3 and went to
"CAL Fctr".  The display was all zeros...no fluctuation.  I measured the
frequency with an external frequency counter, and it showed 12.103MHZ  at
TP3 which is in spec.  I checked the probe with a meter, and there seems to
be continuity from one side of the capacitor to the tip, and the other side
of the capacitor to the 2 pin connector.  Across the capacitor, it is open,
but I expected that, as caps block DC.

I went further in the alignment, and checked the band voltages (80-10mtrs)
at R30, and those also prove to be in spec.  I checked the frequency at
TP1(external frequency meter), and saw 8.4MHZ when I was directed to look at
the value.  So........it appears like the internal frequency meter display
is now inoperative, or something has happened to the probe since alignment
part 1.  I did heat the shrink tubing before test 1, but shrunk it a little
more after.  The tubing did get warm, but I don't think it was warm enough
to damage the capacitor (not sure how I could check if the capacitor was
open...broken lead inside).  I removed the heat shrink to check continuity
of the probe.  If anyone could shed some light on this, I would appreciate
it a bunch.  I am going to aassume I have a bad probe to start.  I can't do
anything further without the internal probe working.  I'll probably head to
"rad shack" to buy another capacitor and rebuild the probe.  I don't think
they carry caps at 10pf though.  Would an .01uF or .001uF work?  Thanks in
advance.

Regards

H. Ed Miller
AA5JO

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