KAT100 problems...

[Mike Sexsmith]

Hello all,

  I have a K2 setup (#4819) with the 100 watt tuner/amplifier in separate
EC2 enclosure. Things have been FB for 3-4 months, but recently while using
100 watts the tuner is unable to get below a 9.9 SWR on 80 meters, even
though other bands tune fine. KAT100 Tuner also does not seem to remember
tune settings anymore when returning to a previously tuned frequency. It
will retune from scratch each time...  I rotated through the relays and all
seem to click ok, although the relay for 80 m seems to sound slightly
different...When using just the base K2 separated from EC2 the KAT2 internal
tuner works fine and remembers settings. Board parts placement and
solderwork appears ok.

   Is the relay itself the most likely culprit, or should I be looking at
something else first?

Could someone please point me towards things to check in order of
likelyhood? Thanks for any help!


Mike Sexsmith
W7MSX


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[Chuck Gehring]

Mike Sexsmith wrote:
>   I have a K2 setup (#4819) with the 100 watt tuner/amplifier in separate
> EC2 enclosure.

Mike,  
My K2/100 is also set up with my KAT100/ KAP100 in a separate EC2 enclosure.  Last month I experienced a similar problem on 30 meters.  Again I disconnected the KAP100 and KAT100 running the K2 with my internal KAT2 internal tuner.  The KAT2 tuned everything fine.  I reconnected everything, and then retuned every band using a dummy load. No improvement.  I checked my coax, BALUN and ladder line to my antenna.  I couldn't find any problems but adjusted the routing of my ladder line and then everything tuned up fine.  I really don't think I fixed anything it just seemed to clear itself.  

 I know this doesn't help your situation, but at least you know your  not the only with this problem.  I would be interested in hearing any solutions or recommendations that you discover.

73 KI4DGH
Chuck Gehring

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[Pat n8vw]

On Tue, 29 Nov 2005 07:36:02 -0800, "Mike Sexsmith"
<[hidden email]> wrote :

>
> Hello all,
>
>   I have a K2 setup (#4819) with the 100 watt tuner/amplifier in separate
> EC2 enclosure. Things have been FB for 3-4 months, but recently while using
> 100 watts the tuner is unable to get below a 9.9 SWR on 80 meters, even
> though other bands tune fine. KAT100 Tuner also does not seem to remember
> tune settings anymore when returning to a previously tuned frequency. It
> will retune from scratch each time...  I rotated through the relays and all
> seem to click ok, although the relay for 80 m seems to sound slightly
> different...When using just the base K2 separated from EC2 the KAT2 internal
> tuner works fine and remembers settings. Board parts placement and
> solderwork appears ok.
>

I wonder if this is RF getting into the tuner.  With mine on 80m I have to
reduce power to < 11 watts to tune either antenna (zepp/80m inv-l) in the CW
section of the band.  If I don't the tuner goes crazy and somtimes turns
itself back to CALP or the leds start acting weird or it looks like it has
tuned, but it once you tx at full power the swr is full scale.  On 80m phone
I don't have these issue.  On 160m it tunes the zepp no problem.  

Pat N8VW

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Hello Mike,

the problem sound familar to me. When i build KAT100 everything worked
fine for some hours. After a while same problem like you described
appeared on my KAT100.

One relay click sounds a bit different and i could not match all bands
anymore. I thought a relay would be not okay, but the reason was a
defect in one of the small condensators connected to a relay.

How i identified the component :

I turned ATU to Cal mode and meassured voltages on all 6B595 pins
connected to a relay. I found one voltage below power supply voltage.
After replacing the condensator it was working fine again.

It happends two times allready that a small condensator failed in my
KAT100.
 

73 de Joerg (DL3QQ)

-----Original Message-----
Date: Tue, 29 Nov 2005 16:36:02 +0100
Subject: [Elecraft] KAT100 problems...
From: "Mike Sexsmith"
To: [hidden email]


Hello all,

  I have a K2 setup (#4819) with the 100 watt tuner/amplifier in
separate
EC2 enclosure. Things have been FB for 3-4 months, but recently while
using
100 watts the tuner is unable to get below a 9.9 SWR on 80 meters, even
though other bands tune fine. KAT100 Tuner also does not seem to
remember
tune settings anymore when returning to a previously tuned frequency. It

will retune from scratch each time...  I rotated through the relays and
all
seem to click ok, although the relay for 80 m seems to sound slightly
different...When using just the base K2 separated from EC2 the KAT2
internal
tuner works fine and remembers settings. Board parts placement and
solderwork appears ok.

   Is the relay itself the most likely culprit, or should I be looking
at
something else first?

Could someone please point me towards things to check in order of
likelyhood? Thanks for any help!


Mike Sexsmith
W7MSX


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