Re: K3/100 and KPA3 Rev C Tech Alert - Important


Eric Swartz - WA6HHQ, Elecraft
 

Yup. As noted at the beginning of my post and in the alert .pdf, you are way outside the s/n and date range.

We also check for this on all repair / upgrade K3s coming through our tech group.

73, EricĀ  WA6HHQ



--- In Elecraft_K3@..., John Merrill wrote:
>
> Mine is there for repair at this moment, serial #2555 purchased in Jan 2009.
> I assume mine should be ok.
>
> 73,
> John N1JM
>
> On Tue, Nov 17, 2009 at 5:05 PM, wa6hhq wa6hhq_lists@... wrote:
>
> >
> >
> > *Spurious TX sidebands due to C3 installation on early Rev C KPA3 PC
> > boards.*
> >
> > * *
> >
> > *We have determined that a small number of K3/100s and KPA3s left the
> > factory earlier this year with capacitor C3 installed by mistake on early
> > Revision C KPA3 PC boards. * This part location should be empty on Rev. C
> > KPA3s. Installation of C3 causes the PA bias supply to oscillate on some
> > KPA3s at approximately 15-20 kHz, resulting in spurious TX sidebands at that
> > spacing from the carrier.
> >
> >
> >
> > *S/N & Date** Range**: A small number of K3/100s within* *approximately
> > S/N 3000-3138*. These radios were shipped approximately *April 30 to June
> > 2, 2009*. Upgrade or repair KPA3s sent separately during this time period
> > may also be affected.
> >
> >
> >
> > *After June 2, 2009, this problem was corrected for all K3/100s s/n 3139
> > and later, and all Rev C KPA3s bought as an upgrade. *This alert *does not
> > * apply to Rev C KPA3s shipped after June 2, 2009.
> >
> >
> >
> > *Symptom:* A strong TX spur, approximately -20 dB down from peak transmit
> > power, spaced approximately 15-20 kHz on each side of the operating
> > frequency.
> >
> >
> >
> > *Corrective Action:* Remove capacitor C3 from the Rev C KPA3 PCB as
> > described in our detailed Tech note.
> >
> >
> > A detailed Tech. Alert App note (.pdf) can be downloaded from:
> > http://www.elecraft.com/K3/mods/K3%20Technical%20Alert%201.pdf
> >
> > It contains detailed info and pictures.
> >
> > Its also linked to from our K3 Mods and App notes Page:
> > http://www.elecraft.com/K3/k3_app_notes.htm
> >
> > We apologize for this issue. We thought we had contacted all of the K3
> > owners affected, but we have found a few we missed, so we are posting this
> > here.
> >
> > If after reading the Tech. Alert you have questions, please feel free to
> > contact our Tech. group at k3support@... or via phone at
> > 831-763-4211
> >
> > 73, Eric WA6HHQ
> >
> >
>

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