K2 Help need

[Gregg W6IZT]

I am current operating /KH6 and my K2 has developed a problem (it was working fine.) I am using a K2/100 with the KAT100 tuner. The problem only occurs on high power.

The KAT100 tunes the antenna to a near 1:1 swr on all bands. Key down all is OK, on key up the swr jumps to a very high level, this occurs on all bands. I am guessing the KPA100 is going spurious on key up.

Any ideas on where to look for the problem, other than generally in the KPA 100?

Thanks
Gregg


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[Don Wilhelm-3]

Gregg,

That definitely sounds like your KPA100 is oscillating.  Do not allow it
to do that for more than a few seconds because the oscillation can cause
the demise several components.

Has your KPA100 been upgraded with the KPA100UPKT?  Alternately, is this
a new KPA100 that was shipped in the last 2 months of last year?

If the answer to both those questions is 'NO', then I strongly recommend
that you add the KPA100UPKT as the first order of business.

If the answer to either question is "YES", then please physically
inspect KPA100 C31 - if it is not a .22 uF capacitor, then obtain the
proper .22 uf capacitor from [hidden email] and replace it.

73,
Don W3FPR

[hidden email] wrote:
> I am current operating /KH6 and my K2 has developed a problem (it was working fine.) I am using a K2/100 with the KAT100 tuner. The problem only occurs on high power.
>
> The KAT100 tunes the antenna to a near 1:1 swr on all bands. Key down all is OK, on key up the swr jumps to a very high level, this occurs on all bands. I am guessing the KPA100 is going spurious on key up.
>
> Any ideas on where to look for the problem, other than generally in the KPA 100?
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[Vic K2VCO]

[hidden email] wrote:

> I am current operating /KH6 and my K2 has developed a problem (it was
> working fine.) I am using a K2/100 with the KAT100 tuner. The problem
> only occurs on high power.
>
> The KAT100 tunes the antenna to a near 1:1 swr on all bands. Key down
> all is OK, on key up the swr jumps to a very high level, this occurs
> on all bands. I am guessing the KPA100 is going spurious on key up.
>
> Any ideas on where to look for the problem, other than generally in
> the KPA 100?

An emergency fix might be to change the length of the feedline to the
antenna. It might help (although I never tried this) to change the
length of the coax between the K2 and the KAT100.

In my opinion, this is problem in the KPA, and Elecraft will give you
guidance -- there are several mods that apply to it.
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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[jeff martin-6]

Don,
I just read your reply to Gregg. I am just starting to
build a KPA100, purchased May 2006. I read your
answer, and ordered the KPA100UPKT upgrade. My
question concerns your reference to C31 needing to be
.22 uF...My manual (Rev C) and the Rev E manual both
show it as .033 Uf, I believe. Did I miss something,
or is there another tech note I need to read and
address?
 
Thanks for your help.
 
Jeff
N7KRT


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[Ken Wagner K3IU]

Hi Jeff:
Check Errata Sheet E-2 for the KPA100. New value is ".22μF (“μ22J63”) 63V"
73,
Ken K3IU


jeff martin wrote:

> Don,
> I just read your reply to Gregg. I am just starting to
> build a KPA100, purchased May 2006. I read your
> answer, and ordered the KPA100UPKT upgrade. My
> question concerns your reference to C31 needing to be
> .22 uF...My manual (Rev C) and the Rev E manual both
> show it as .033 Uf, I believe. Did I miss something,
> or is there another tech note I need to read and
> address?
>  
> Thanks for your help.
>  
> Jeff
> N7KRT
>
>
> --------------------------------------------------------------------------------
>
>
>
>       ____________________________________________________________________________________
> Shape Yahoo! in your own image.  Join our Network Research Panel today!   http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.asp?a=7 
>
>
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[Ron D'Eau Claire-2]

The current errata is E3. E2 is also correct to answer Jeff's question.

E3 removes reference to the bodies of some RFCs as being "tan". They are no
longer identified using body color: only by the color stripes indicating
their value.

Ron AC7AC

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[jeff martin-6]

Thanks all, for the clarifications. I just started the
build, so I am not so far into it I have to remove any
components. I have printed the latest revision manual
and errata and will carry on using it.

Thanks again!

Jeff
N7KRT
K2 #5471


 
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