[Elecraft] K2: No recieve/power out on 20M thru 10M

[Marc Glade]

Well, after following Tom's (N0SS) Cheap 'N Dirty Signal Tracing Guide
it would seem that the problem does fall within the band-pass filter
as injecting a signal at D6 works fine but at W6 hardly anything comes
through for the aforementioned bands. Now I'm even more confused
though as I don't see how one fault can cause issues on 20M-10M, but
leave 30M-160M unaffected. That would leave me to believe that there
are multiple faults in the band-pass filter which while possible,
strikes me as very odd since everything was originally working fine
and the now affected bands all started showing problems at the same
time.

Marc W1RSC
K2 #4360


On Wed, 10 Nov 2004 08:11:17 -0500, W3FPR - Don Wilhelm
<w3fpr at earthlink.net> wrote:
> Marc,
> 
> There is nothing in the bandpass or lowpass filters that would cause good
> behavior below the 10 mHz band and bad performance above that.
> 
> I suggest that one of the few things that could cause such behavior is the
> VCO.  Use CAL FCTR with the probe in TP1 and check the VCO frequency on
> those bands.  The frequencies should be close to those listed in the VCO
> Table of the K2 Schematic Key (appendix B of the manual).  Also, build the
> RF Probe and check the VCO voltage as indicated in page 10 of the
> Troubleshooting section (Appendix E).
> 
> 73,
> Don W3FPR
> 
> 
> ----- Original Message -----
> From: "Marc Glade" <mglade at gmail.com>
> To: <elecraft at mailman.qth.net>
> Sent: Wednesday, November 10, 2004 1:23 AM
> Subject: [Elecraft] K2: No recieve/power out on 20M thru 10M
> 
> >I am the proud owner of K2 #4360. When I first put the unit together
> > everything checked out smoothly and there were no issues. I have since
> > added the KSB2, KIO2, KAT2, K160RX, KNB2, K60XV, and KAF2. No issues
> > appeared to arise after adding the modules. I had to set the K2 aside
> > for a month due to other commitments and upon returning to it about a
> > month ago I noticed I had no power out on any band. A quick check and
> > replacement of R50 solved this. Except now I noticed that on 20M thru
> > 10M with a slight exception on 15M I still had no power out and also
> > that even with max AF gain the signal from a connected N-gen was
> > barely perceptible. 15M is a little different in that I can get a max
> > power out of 1.5W on that band and receive is also a little better but
> > not by much. On 160M thru 30M the rig functions perfectly fine. I have
> > tried re-aligning the bandpass filters multiple times to see if that
> > was were the problem was but could not resolve the issue. I have spent
> > hours looking over the rf board with a magnifying glass and a dmm
> > trying to find a fault or bad solder joint but haven't found anything.
> > My knowledge in this area is limited and I feel like I've run into a
> > brick wall with this issue. If there is anyone that has any
> > suggestions I eagerly await them.
> >
> > Thank You,
> > Marc W1RSC
> > K2 #4360
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