[Elecraft] Low sensitivity and low power calibration failure

Brett Howard brett at livecomputers.com
Tue Jul 8 11:36:46 EDT 2008


This is in a completely different area but trust me on this one...  See
if you can find R66 on t he bottom of the RF board toward the right side
of the unit when you're looking at the unit from the front.  Its just
above Q8 and Q9.  Measure the resistance of R66 and post that here.

On Tue, 2008-07-08 at 03:02 -0700, OE5CSP-Chris wrote:
> I still have problems with my K3.The sensitivity is very low and I
>  can´t do the low power tx calibration.
> I loaded the latest
> firmware and checked all the settings again and
> again.
>  Gary Surrency, from the elecraft support, suggested to do a few
> measurements.These are the results.A friend
> helped me, because I don´t have an rf-probe myself.The results are at the
>  end of this page!
>  Garry is on a trip and he´ll be back on Thursday, so he can´t help me
> now.I´ve got enough time to do some repair work and any help would be
> appreciated.
> 
> > >
> > > 111mV RMS at the center pin of coax jumper from the KREF2 board, that
> > goes into RF board connector J65.
> > >
> > > 37mV RMS on the right pin on both sides of the crystal filter pins.
> > >
> > > 346mV RMS at the BPIF jumper to the left of the KNB3 board.
> > >
> > > 189mV RMS at jumper W4 near the KIO3. This may be a jumper wire that is
> > plugged into J64A on later sn. K3s.
> > >
> > > 176mV RMS at P71A pin 3 on the LPA.This is near the left rear of the
> > LPA, right across from the KIO3 board. Pin 1 is to the rear.
> > >
> > > 15.5V RMS at P71C pin 1 on the LPA. This connector is at the rear of the
> > LPA board. Pin 1 is on the left.
> > >
> > > Examine the parts and connections under the RF Board in the bandpass
> > filter area, to see if there are any poorly soldered or damaged parts.
> > >
> > >
> > > My results:
> > > Board connector J 65 shows 35-40mV. All other measurements were 0.
> > > My friend thinks it´s maybe a problem with the 2nd mixer.We also looked
> > for damaged parts but we could not find any.
> > >
> > > Can you help?
> > >
> > >
> > > vy73 Chris-OE5CSP
> > >   
> > 
> > -- 
> > 73 Richard AD7FZ
> > Elecraft Support
> > support



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