[Elecraft] High SWR in to dummyload on 6/10M

[Peter]

Hi Joe

Thanks for your response.
I have reinstalled the ATU in the K3, as you indicated, turned on the 
tuner and tuned it in a dummy load.
Now everything is OK again, also in bypass mode.

That was simple :-)

73 Peter
PC2A

Op 27-4-2026 om 17:16 schreef Joe Subich, W4TV via Elecraft:
>
> Did you try engaging the KAT3 on 10 and 6 meters and *tuning* into
> the dummy load?  After that, bypass the tuner and check the SWR.
>
> The KAT3 (as opposed to the KAT3A) has no hard bypass.  To bypass
> the tuner, the K3 selects the "tuned to 50 Ohm" state.
>
> Note: the tuning solutions (including bypass) are stored separately
> for ANT 1 and ANT 2 but are not reset if one changes KAT3 boards.
>
> 73,
>
>    ... Joe, W4TV
>
>
> On 2026-04-27 10:19 AM, Peter via Elecraft wrote:
>> Hi
>>
>> I have a K3 that needs some maintenance.
>> The SWR on 10 and 6 meters is high (1:2).  On the bands below it is 
>> OK (1:1).
>> The ATU had a burnt L  (L10 (IF stage trap)). Both the C and the L 
>> have been removed and a jumper has been installed.
>>
>> After reinstalling the ATU, there was hardly any change. The SWR was 
>> now 1:1.9 on 10 and 6 meters.
>> After this, the ATU was swapped with another ATU from a properly 
>> working K3.
>> However, the SWR on 10 and 6 meters remains unchanged and high.
>>
>> A second test was swap the output pin from ATU to PL259. On ANT 1 the 
>> SWR remained bad and on ANT 2 it was good.
>>
>> Then, I directly connected the PL259 on the back to P70 on pins 17-20.
>> Now the SWR is OK on all bands.
>>
>> In my view, the cause lies in the control via the P70 pin 1-5 because 
>> I tested it with 2 ATUs that react the same way.
>> Does anyone have a tip on how to check its operation?
>>
>> 73 Peter
>> PC2A
>
>
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