Re: [Elecraft] KAT3 (not KAT3A) issue - older K3 take note

jeff stai wk6i

hi Alan - Thank you, I have done those mods as well, but this one was a surprise! 73 jeff wk6i

On Mon, Jun 14, 2021 at 3:44 PM Alan Baker <g4gnx@...> wrote:
There's a whole stack of mods done over the years. They were on the
Elecraft website in pdf format. If you can't find them, I have all of
them here and have performed most of them on an older K3.


Alan. G4GNX

------ Original Message ------
From: "Jeff Stai" <wk6i.jeff@...>
To:; "Elecraft Mailer" <elecraft@...>
Sent: 14/06/2021 22:36:08
Subject: [Elecraft] KAT3 (not KAT3A) issue - older K3 take note

>TL;DR: Got a KAT3 in your K3? Next time you have your K3 open, pull out
>KAT3 and preemptively remove L10 and C10, and replace with a jumper. You
>don't need them and they are probably messing you up at times.
>(Are there any other older K3 issues like this? Tell me!)
>I have an early model K3 that still has all of its original modules. I was
>having an issue where the power output was sometimes dropping to just a few
>Running the TX calibration would sometimes fail completely with weird error
>messages, but if I could get it to run it would get through most of the way
>but always fail on 52MHz due to high SWR (over 2). With a dummy load or a
>matched antenna, SWR was over 2 also in normal operation.
>Of course, this low power situation would magically correct itself after
>some poking around, though the 52MHz high SWR was consistent.
>I finally decided that I wanted to do some 6m operating and I used the KAT3
>to get matched to the load. I would just operate until something finally
>decided to fail fully.
>It did. After a few hours C10 on the KAT3 blew, LOUDLY and smokily.
>Undoubtedly due to some crazy high voltages presented by the tuner.
>After some sleuthing in the Elecraft reflector I found the C10/L10 filter
>issue being well discussed. Pulling them out and jumpering solved all my
>issues. With the K3, anyway. :)
>This filter was not included in the KAT3A. If you have one of those, you're
>good. If you want to know more about the history of this filter it's easy
>enough to find in the email archives. :)
>Hope this helps - jeff wk6i

Jeff Stai ~ WK6I ~ wk6i.jeff@...
RTTY op at W7RN
Twisted Oak Winery ~

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