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Probelm with KPA-100

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Dave White-3

Probelm with KPA-100

I have a KPA-100 that is not putting out any power. The K2 operates fine
using the standard "QRP" power (up to 10 watts). Power is good and the SWR
is low. When the power control is advanced to bring in the KPA-100 (relay
"click"), the power reading immediately goes to "1" and there is no power
output. The KPA-100 is recognized and the PA is turned "ON" in the setup
menu. Everything else appears normal .This is a used KPA-100 and there are
no obvious signs of damage; the construction quality looks to be excellent.
The previous owner said there was no history of problems.

Any quick ideas on where to start the troubleshooting process? I have some
"hobbyist" test equipment and "modest to good" troubleshooting skills.

Thanks in advance for your help.

Regards

Dave White, VE6DRW
[hidden email]

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Don Wilhelm-4

Re: Probelm with KPA-100

Dave,

How is receive with the KPA100 in-line? If receive is degraded, then
the KPA100 LPF may be the problem, but if power output is the only
problem than the PA transistors (or the T/R switch) is the area that
needs attention.

The first step that I would take is to check the bias adjustment - do
the steps indicated in the manual. Secondly, check the RF voltages at
the input to the KPA100 and the bases of the PA transistors - if the
bases are receiving RF, then the KPA100 should amplify.

73,
Don W3FPR

Dave White wrote:

> I have a KPA-100 that is not putting out any power. The K2 operates
> fine using the standard "QRP" power (up to 10 watts). Power is good
> and the SWR is low. When the power control is advanced to bring in
> the KPA-100 (relay "click"), the power reading immediately goes to "1"
> and there is no power output. The KPA-100 is recognized and the PA is
> turned "ON" in the setup menu. Everything else appears normal .This is
> a used KPA-100 and there are no obvious signs of damage; the
> construction quality looks to be excellent. The previous owner said
> there was no history of problems.
>
> Any quick ideas on where to start the troubleshooting process? I have
> some "hobbyist" test equipment and "modest to good" troubleshooting
> skills.
>
> Thanks in advance for your help.
>
> Regards
>
> Dave White, VE6DRW
> [hidden email]
>
>
>
> _______________________________________________
> Elecraft mailing list
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> You must be a subscriber to post to the list.
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AJSOENKE

Re: Probelm with KPA-100

In reply to this post by Dave White-3

Although the KPA is installed and is responding to setup configs, there is
one area that is sometimes overlooked. The internal RF connection to the Main
board needs to be connected correctly, and the antenna needs to go to the KPA
SO239, not the Mainboard BNC.

Al WA6VNN
+++++++++++++++++++
In a message dated 6/15/2008 7:46:16 P.M. Pacific Daylight Time,
[hidden email] writes:
Dave,

How is receive with the KPA100 in-line? If receive is degraded, then
the KPA100 LPF may be the problem, but if power output is the only
problem than the PA transistors (or the T/R switch) is the area that
needs attention.

The first step that I would take is to check the bias adjustment - do
the steps indicated in the manual. Secondly, check the RF voltages at
the input to the KPA100 and the bases of the PA transistors - if the
bases are receiving RF, then the KPA100 should amplify.

73,
Don W3FPR

Dave White wrote:

6:02 PM
>
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