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KPA100 Installation Q:

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andyatd

KPA100 Installation Q:

Does the KPA100 alignment procedure need to be followed if installing an already aligned and working KPA100 in a different K2/10 that has been used QRP only? This is an early generation KPA100.

Thanks.

Andy
N3LCW

Don Wilhelm-4

Re: KPA100 Installation Q:

Andy,

I would highly recommend installing the KPA100UPKT in any KPA100 that
does not already have it installed. If there are any signs of
instability, the KPA100UPKT is the first line of defense.

To answer your question directly - maybe and maybe not. The
installation of a KPA100 in those K2s below SN 3000 must have the
Control Board changes installed (they are already present on the board
for K2s above SN 3000).

The menu parameters must be set for the KPA100 installation, so it is
not as easy as "plug it in and do nothing".

There are only 2 areas of "alignment" for the KPA100. The first is
setting the bias (which I would check carefully on any KPA100 install
even though the prior owner may have thought it was correct).
Secondly, there is the wattmeter calibration, which I would recommend
just in case there is some difference in the VRFDET response from one K2
to another.

These alignment and calibration steps can be done quickly and easily,
and I would not recommend skipping them, even if you have purchased a
KPA100 from another owner who indicated it was working fine for him.

If you did not purchase the KPA100, but instead are transferring it from
one K2 that you have to another, these steps may not be required, but I
have found during repairs that several KPA100s did not have the bias set
correctly or did not produce correct wattmeter readings, so I would
recommend that you walk through the alignment and calibration procedures
just to assure yourself that it was set up correctly.

The tools needed are only two - a DC current meter with a scale of 2
amps or greater and capable of indicating a current rise of 0.40 amps.,
and an external wattmeter having an accuracy equal to (or greater than)
the accuracy you desire for the KPA100 power indication. The KPA100
alignment and calibration will only be as accurate as the tools you
use. Know the limits of your tools, and trust them only to the extent
of those limits - a current meter with 10 percent precision can only be
trusted to 2 significant digits even though it may indicate 4 or 5 digits.

73,
Don W3FPR

On 8/20/2011 11:13 PM, andyatd wrote:

> Does the KPA100 alignment procedure need to be followed if installing an
> already aligned and working KPA100 in a different K2/10 that has been used
> QRP only? This is an early generation KPA100.
>
> Thanks.
>
> Andy
> N3LCW
>
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/KPA100-Installation-Q-tp6707741p6707741.html
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andyatd

Re: KPA100 Installation Q:

Don,

Reading the KPA100 manual I anticipated re-alignment and setup would be a good idea. The procedure looks straightforward and I do have adequate equipment for the process. The KPA100 will be installed on a 48xx series serial number K2 and I am not sure whether the KPA100UPKT has been installed or not, but I will do so if it is not.

Thank you for your recommendations.

Andy
N3LCW

Don Wilhelm-4

Re: KPA100 Installation Q:

Andy,

If the KPA100 has red core toroids at L15 and L16, it is the old level
and the KPA100UPKT should be installed. If there are blue core toroids
at RFC1 and L16, it has already been installed.

73,
Don W3FPR

On 8/21/2011 2:30 AM, andyatd wrote:

> Don,
>
> Reading the KPA100 manual I anticipated re-alignment and setup would be a
> good idea. The procedure looks straightforward and I do have adequate
> equipment for the process. The KPA100 will be installed on a 48xx series
> serial number K2 and I am not sure whether the KPA100UPKT has been installed
> or not, but I will do so if it is not.
>
> Thank you for your recommendations.
>
> Andy
> N3LCW
>
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/KPA100-Installation-Q-tp6707741p6707897.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>