http://elecraft.85.s1.nabble.com/K2-100-Has-No-Output-on-80-or-40-When-Hot-tp5124474p5133149.html
Thank you for your help. Yes, it appears to be the VFO. The VCO readings
hot the readings are near 15,600 for 40 and 17,257 for 80. No wonder I
> -----Original Message-----
> From: Don Wilhelm [mailto:
[hidden email]]
> Sent: Tuesday, June 01, 2010 6:08 AM
> To: Phil-W6TQG
> Cc:
[hidden email]
> Subject: Re: [Elecraft] K2/100 Has No Output on 80 or 40 When Hot
>
> Phil,
>
> To use the base K2 BNC antenna jack, you must remove the
> KPA100 - if you
> attempt to use that jack, the load impedance between the base
> K2 and the
> KPA100 will not be correct, and "strange happenings" will be present.
>
> A total lack of power (yes, a display of 0.1 or 0.2 watts is
> actually no
> power out) is most likely a problem either in the bandpass
> filter or a
> problem with the VFO. Try the VFO first - set the frequency
> to the low
> end of the band and check the frequency with the counter probe in TP1
> using CAL FCTR - compare your frequency reading with the chart on the
> Schematic Key page. If you want to calculate the proper VFO
> frequency
> it should be within a few kHz of the frequency on the dial
> plus 4915 for
> bands below 15 meters.
>
> Check all the components in the bandpass filter area for 40m
> and for 80
> meters. On 40 meters, be certain C6 is properly installed
> between the
> two outer holes of the J15 position (the center hole should be empty).
>
> 73,
> Don W3FPR
>
> Phil-W6TQG wrote:
> > Every since the last Field Day, my K2/100 (#3713) loses
> output, and the
> > receiver goes dead, on 40m and 80m when it gets hot. This occurs for
> > power levels of 9 watts and 100 watts. The 30m through 10m
> bands are OK.
> > I can easily replicate the problem when the power amp is
> connected, but
> > so far it seems to be OK when it is completely unplugged
> from the K2.
> >
> > Turning off the power amplifier through the Secondary Menu
> does not make
> > a difference. While transmitting at 9W, the readings on the
> display for
> > 40 and 80 are "0.1 1.01 - 1". With the power amplifier
> connected to the
> > K2, I temporarily connected the antenna to J4 on the K2, so
> that I could
> > bypass the power amplifier path. This did not help the dead
> reception on
> > 40 or 80. I also tried connecting a dummy load through a
> power meter to
> > J4 and transmitting at 9W. Again 40 and 80 didn't work but
> the higher
> > bands were OK.
> >
> > I am assuming that the problem is in the LPF of the power
> amplifier, but
> > am not sure 30m is OK, while 40 and 80 are not. Any hints would be
> > appreciated.
> >
> > 73,
> > Phil W6TQG
> >
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