K3 power output instability

[w7xu]

Running the low and high power TX gain calibration via the K3
Utility gave the following result:

"TX Gain calibration failed because power reading did not
converge to a consistent value.  5W calibration failed."

"TX Gain calibration failed because power reading did not
converge to a consistent value.  50 W calibration failed."

The low power calibration failed on 40 meters and stopped there.
  The 50 W calibration failed on 160 meters and stopped there.

The radio also gave an error message: ERR TXG (Transmit gain
constant out of range).

73,  Arliss



Arliss,

I would suggest that you run the Transmit Gain Calibration and
see if that improves the situation.

73,
Don W3FPR

On 3/13/2013 9:10 PM, Arliss wrote:
 >I'm experiencing a problem with instability in power output
 >from my K3/100.  No word back from Elecraft yet (it's only been
 >a few days), so I thought I'd try here.
 >
 > The problem is that at relatively low power output levels
 >(approximately 10 to 40 watts), the power output does not
 >remain constant.   If I engage TUNE, the power will vary
 >plus/minus 3 or 4 watts, then jump up briefly by as much as 10
 >watts or more before resuming smaller excursions.  Although the
 >power variations are brief, they cause the grid protection
 >circuit in the amp to trip.  This behavior seems to be
 >independent of mode and frequency.
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[Don Wilhelm-4]

Arliss,

If you do not have the latest firmware loaded along with the latest K3
Utility, please load the latest and try again.  If it continues to fail,
contact [hidden email].

73,
Don W3FPR

On 3/13/2013 11:12 PM, Arliss wrote:

> Running the low and high power TX gain calibration via the K3 Utility
> gave the following result:
>
> "TX Gain calibration failed because power reading did not converge to
> a consistent value.  5W calibration failed."
>
> "TX Gain calibration failed because power reading did not converge to
> a consistent value.  50 W calibration failed."
>
> The low power calibration failed on 40 meters and stopped there.  The
> 50 W calibration failed on 160 meters and stopped there.
>
> The radio also gave an error message: ERR TXG (Transmit gain constant
> out of range).
>
> 73,  Arliss
>
>
>
> Arliss,
>
> I would suggest that you run the Transmit Gain Calibration and see if
> that improves the situation.
>
> 73,
> Don W3FPR
>
> On 3/13/2013 9:10 PM, Arliss wrote:
> >I'm experiencing a problem with instability in power output >from my
> K3/100.  No word back from Elecraft yet (it's only been >a few days),
> so I thought I'd try here.
> >
> > The problem is that at relatively low power output levels
> >(approximately 10 to 40 watts), the power output does not >remain
> constant.   If I engage TUNE, the power will vary >plus/minus 3 or 4
> watts, then jump up briefly by as much as 10 >watts or more before
> resuming smaller excursions.  Although the >power variations are
> brief, they cause the grid protection >circuit in the amp to trip.  
> This behavior seems to be >independent of mode and frequency.
> ______________________________________________________________
> 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
>

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[Andy Wood]

Hi Arliss,

I recently had a similar problem with my K3. I contact Elecraft and received this response from Gary:

---------------------------------------------
See if it will produce 12w on 160-10m, and at least 8w on 6m, in Tune, with the KPA3 menu set to Bypass. The VFO should be near the middle of the band.

Check the 3 LPA mounting screws on the bottom panel are all tight too.

Be sure it passes VCO MD CAL too, and the ADC REF menu is set as shown below:
---------------------------------------------

In my case, running VCO MD CAL cured it. I also asked Gary why this value may have been corrupted - here is his response:
"It does change sometimes with age or changes in temp, humidity, or altitude. Not a bad idea to redo VCO MD CAL from time to time."

Andy  VK4KY

[Lee Trout]

I've mentioned this before, but several seemingly inexplicable problems I
have had with my K3 have been solved by simply doing a Parameter
Initialization (see manual.)  Just be sure to save your configuration
first.  May not help, but doesn't take long so always worth a try.  One
caveat, that Don Wilhelm pointed out to me:

*Ideally, that saved configuration file should be one that was obtained
before the problem came up. If a configuration file is generated right
before the EEINIT [**Parameter Initialization], the same problem may be
re-loaded afterwards.

73, Lee (K9CM)


*
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