[Elecraft] K2 Over Current High Power 40 Meters.

[Johnny Matlock]

Thanks Don
I will check these things.
This may be over my pay grade?
The CPU has been upgraded, but I’m not home to check the Revision.

I know your retired, but do you still do any repairs part time?

Thanks
Johnny AC0BQ



On Tue, May 28, 2019 at 8:25 AM Don Wilhelm <donwilh at embarqmail.com> wrote:

> Johnny,
>
> You have a Power Control problem - alignment is not going to fix it, and
> you will have to correct it and have proper power control before any of
> the alignment results make sense.
>
> Since you indicate that the problem exists with only the base K2, that
> is the place to start troubleshooting.  Do not connect the KPA100 - it
> must be physically removed.
>
> Set the power to about 2 watts, but monitor the actual power with an
> external wattmeter and drive a dummy load.
> Then do a TUNE while monitoring the VRFDET signal.  It is easiest to
> probe at Control Board P4 pin 10.  Limit the time for a TUNE to 15 to 20
> seconds if the actual power is going to maximum (it may be as high as 19
> watts).
> If the DC voltage on VRFDET is near zero, the RF Detector is not working
> for some reason - replace RF Board D19 and try again.  If still no
> voltage on VRFDET, reflow the soldering on RF board R66, R67, R68, R69
> and C77.
>
> Should you find a DC voltage that is above 3.5 volts, D19 is working
> fine, but the MCU is not responding.  The most likely problem is that
> the MCU (Control Board U6) has a damaged input at pin 2.  In that case,
> it has to be replaced.
> Here things may get a little complicated depending on the level of your
> current MCU.  If it is 2.04P or 2.04r, you can order FW-K2MCU and simply
> replace U6.  If it is less than that, you must order FW-K2MCIO and
> replace both CB U6 and RF Board U1.
>
> So hope the problem is D19, that is inexpensive, but the firmware is
> expensive.
>
> 73,
> Don W3FPR
>
> On 5/28/2019 7:39 AM, Johnny Matlock wrote:
> > Gm Group
> > I connected a newly acquitted “twin” Amp and Tuner in a separate
> enclosure
> > setup this weekend.
> >
> > While bench testing with a dummy load  I noticed that I would get high a
> > current message if the power setting was turned over midway, and the amp
> > was trying to produce more than 100 watts!
> >
> >
> > I disconnected the Amp and Tuner, continued to test the bare K2.
> >
> > On 40 meters my power setting  wasn’t tracking the actual output.
> > The actual power out was a lot higher than the radio’s setting.
> >
> > I downloaded the calibration instructions and continued testing.
> >
> > When I Set the power to 2 watts and attempt to peak the 40 meter coils,
> > The power goes up to over 10 watts?
> >
> > I pulled the lids and looked at the connections around the 40 meter
> coils,
> > also I did a reflow on the connections in that area.
> >
> >
> > I’m trying to understand the cal instructions?
> >
> > If you set the control at 2 watts and peak the two coils, and the power
> is
> > higher, how will it track accurately?
> >
> > I’m trying to decide if I have a problem
> > With my Radio, or am I just not understanding the calibration
> instructions??
> >
> > I went to Don’s website and downloaded his condensed instructions, but I
> > was too tired to give them a try!!
> >
>
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