KAT2 Tuner issue (Ant 1 / Ant 2 switching)

[nz8j]

I just discovered that I have a problem with my new (to me) K2. It appears
that the antenna switch is stuck on antenna 1.  Switching between Ant 1 and
Antenna 2 with the feedline on Ant 1 doesn't change a thing in terms of
receive signals. The ANT2 indicator turns on when pressing the ANT 1/2 but
in reality it isn't switching. The tuner works fine when on antenna one.
There are no signals received when the feedline is  on Ant 2 and the
indicator for Ant 2 is illuminated.

 

With the tuner out of line (CALP or CALS) and switching antennas I cannot
hear the relay switch between Ant 1 and Ant 2. If I put the tuner in AUTO
and switch between Ant 1 and Ant 2 I can hear the tuner relays switch.

 

Anyone run into this before? I just discovered this late last night and
haven't taken the cover off yet to investigate. In a quick look at the
schematic it looks like relay K18 is what switches the ant ports.  Curious
if this has been mentioned in the past, I did look at the archives and
didn't find anything related to this.

 

Any ideas or suggestions? I plan on taking a look at the tuner today and
maybe check for voltage on K18. Never having worked on a KAT2 I don't know
how difficult this will be to get at.

 

Thanks

Tim

NZ8J

______________________________________________________________
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
Message delivered to [hidden email]

[Don Wilhelm]

Tim,

When ANT2 is selected, do you hear signals if the feedline is connected
to ANT1?  Are they at the same level as when ANT1 is selected?
If the answer is YES to both questions, then the most likely thing is
that relay K18 is not switching.  If the signals are reduced when ANT2
is selected, then at least K18 is disconnecting ANT1, but ANT2 is not
connected.

If the relay is doing noting at all, it could be either the relay itself
or the output of the firmware that is at fault.

Look for other causes before changing the relay.  I have seen burned
leads between the BNC jack and the board (likely caused by lightning).
Both the center conductor and the shell are connected to the board via
leads on the back of the jack - be sure to check both.

Relays K17 and K18 are on the control board - which is the upper board
when the top cover is turned upside down.

73,
Don W3FPR


On 12/5/2016 8:50 AM, Tim Cook wrote:

> I just discovered that I have a problem with my new (to me) K2. It appears
> that the antenna switch is stuck on antenna 1.  Switching between Ant 1 and
> Antenna 2 with the feedline on Ant 1 doesn't change a thing in terms of
> receive signals. The ANT2 indicator turns on when pressing the ANT 1/2 but
> in reality it isn't switching. The tuner works fine when on antenna one.
> There are no signals received when the feedline is  on Ant 2 and the
> indicator for Ant 2 is illuminated.
>
>
>
> With the tuner out of line (CALP or CALS) and switching antennas I cannot
> hear the relay switch between Ant 1 and Ant 2. If I put the tuner in AUTO
> and switch between Ant 1 and Ant 2 I can hear the tuner relays switch.
>

______________________________________________________________
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
Message delivered to [hidden email]