Re: KPA 500 Low power out.


Jeffrey griffin
 

Ever since I started running the data modes with crappy downsized antennas I have a bandpass repair under my belt. If you are somewhat confident in your soldering abilities it's easy with Elecraft equipment. When you open it up the problem component should be easy to find, and as it's an Elecraft, so the support is excellent. I had a burned out inductor and Elecraft was able to tell me the Digikey part number for the Toroid, and also how many turns. Their support made the repair project a pleasure to do. Good luck with it....

73 Jeff kb2m

-----Original Message-----
From: Elecraft-K3@groups.io <Elecraft-K3@groups.io> On Behalf Of Dave (NK7Z)
Sent: Tuesday, October 19, 2021 2:14 PM
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] KPA 500 Low power out.

Hi,
No problem, that set of graphs will give you what my amp did when it was new... Good luck getting your amp up to power. I am following this thread as it may at some time apply to me...

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources

On 10/19/21 8:16 AM, Mike Streeter via groups.io wrote:
Hi Dave. Thanks for your response. It appears that my original post
may be misleading. The amp in question has always put out 500 watts
with about 30 watts drive until recently when it has started reducing
the output with 30 watts drive down to 100-200 watts out. Even if the
drive is increased to 40 watts (the maximum recommended by Elecraft),
the output is still only 100-200 watts out.

Thanks again, Mike, WM5DX.



On Tuesday, October 19, 2021, 09:00:00 AM CDT, Dave (NK7Z)
<dave@nk7z.net> wrote:



A few years ago, I made an input power, vs. output power, graph of the
KPA500 I own. It is located at:

https://www.nk7z.net/kpa500-input-vs-output-power/
<https://www.nk7z.net/kpa500-input-vs-output-power/>

That set of graph may be of some use in this matter. Click any of the
three graphs to expand that graph.

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net <https://www.nk7z.net> ARRL Volunteer Examiner
ARRL Technical Specialist, RFI ARRL Asst. Director, NW Division,
Technical Resources

On 10/19/21 6:35 AM, Mike Streeter via groups.io wrote:
> Hi Bob, thanks for your input. Yes, 40 watts is excessive, normal
would > be around 30 watts...





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