[Elecraft] K2 showing Lo P on 10 meters, and no transmit power.

[Don Wilhelm]

Chris,

Remove the red ones from C21 and C23, and put the yellow ones in those 
positions.  The red ones go at C44 and C46.
That is indicated in the errata pages.  You should read the errata and 
mark the changes in the manual.
Yes, I realize that the manual states that C21 and C23 have a red 
marking, but that was long ago before the trimmers were changed. Now the 
errata is the only correct source of the latest information.

73,
Don W3FPR

On 6/7/2020 1:29 PM, Christophe GIBERT wrote:
> Thanks Don for the quick answer!
>
> L12 and 13 have the narrow slug adjustment slot.
> C43 and C47 are 33pF
> C42 and C48 are 330 PF
>
> C44 and C46 are yellow. Like C32 and C34. But C21 and C23 are red ... 
> Should C21 and C23 been yellow and C44 and 46 red ?
>
> -- 
> Chris
> ------------------------------------------------------------------------
> *De :* Don Wilhelm <donwilh at embarqmail.com>
> *Envoyé :* dimanche 7 juin 2020 19:12
> *À :* Christophe GIBERT <gibertc at hotmail.com>; Elecraft Support 
> <support at elecraft.com>; elecraft at mailman.qth.net 
> <elecraft at mailman.qth.net>
> *Objet :* Re: [Elecraft] K2 showing Lo P on 10 meters, and no transmit 
> power.
> Chris,
>
> Yes, the bandpass filter seems to be the problem.
> Do you have the correct inductors at L12 and L13 - they should have a
> narrow slug adjustment slot.
> Are the capacitors C43 and C47 actually 33 pF (marked either "33" or 
> "330").
> Are capacitors C42 and C48 actually 330 pF (marked "331").
>
> Are you able to tune 12 meters?  The trimmers at C44 and C46 should have
> red bodies.
>
> 73,
> Don W3FPR
>
> On 6/7/2020 12:55 PM, Christophe GIBERT wrote:
> > Hi Don, I've made some troubleshooting today.
> >
> > Without the KAT2, I've got no power on 10 meters.
> >
> > Visually all is good at bandpass filter for 10/12 meters. I've remade
> > some joints but the problem remains.
> >
> > With the troubleshooting of page 14, here are the values :
> >
> > U10 pin 4 : 0.012 Vrms
> > U9 pin 6 : 0.293 Vrms
> > W6 : 0 or near 0 V
> > So in S1 anode : 0 V or near... It seems to incriminate the bandpass
> > filter or am I wrong ?
> >
> > Please tell ...
> >
> > Thanks a lot.
> >
> > --
> > Chris
> > ------------------------------------------------------------------------
> > *De :* Don Wilhelm <donwilh at embarqmail.com>
> > *Envoyé :* jeudi 4 juin 2020 17:34
> > *À :* Christophe GIBERT <gibertc at hotmail.com>; Elecraft Support
> > <support at elecraft.com>; elecraft at mailman.qth.net
> > <elecraft at mailman.qth.net>
> > *Objet :* Re: [Elecraft] K2 showing Lo P on 10 meters, and no transmit
> > power.
> > Chris,
> >
> > The LoP message indicates that there is not enough power to tune the 
> KAT2.
> >
> > As your first troubleshooting test, unplug the KAT2 (both cables) and
> > try again - connect a dummy load to the lower BNC jack on the base K2.
> >
> > See if you get power output on 10 meters.  If not, look carefully at the
> > bandpass filter for 10/12 meters.
> >
> > If the bandpass filter is OK, then you will have to do Transmit Signal
> > Tracing.  Build the RF Probe if you have not already done that and turn
> > to the Troubleshooting appendix in the manual.  Do the troubleshooting
> > on page 14.  Use 10 meters instead of 40 meters, and tell me at which
> > point the RF voltage is significantly (more than 10%) less than the
> > expected voltage.
> >
> > 73,
> > Don W3FPR
> >
> > On 6/4/2020 9:59 AM, Christophe GIBERT wrote:
> > > Hi folks, I'm done in the building of my #7855 K2 and his KAT2.
> > >
> > > I've got a problem on 10 meters.
> > >
> > > For example I put the VFO on 28 360 Khz and I press down TUNE, to 
> tune.
> > >
> > > The screen shows a "Low P" message. When I try to transmit on this
> > band, where is no power at all, the S Meter not move at all. (Problem
> > with my antenna connected even with a good 50 ohms dummy load). All is
> > good on the other bands.
> > >
> > > My K2 is KAT2 and KSB2 equiped.
> > >
> > > Some idea on where investigate ?
>