[Elecraft] Fw: Sudden erratic power/high current problems with K2

[Bill Carpenter]

After some investigation I found that the braid of the coax for the Aux RF 
had frayed at the KPA100 board to just a couple of strands.  Hoping this was 
the problem I repaired it but no change.  This all seems to be caused by the 
K2 power control being all or none with no intermediate settings.  In low 
power as I turn the knob clockwise it goes from minimal power to full QRP of 
about 12 watts suddenly and when the high power comes on it jumps to full 
output.  How do I approach this problem?  Is it ALC related?
----- Original Message ----- 
From: "Bill Carpenter" <nz0t at cox.net>
To: "elecraft list" <elecraft at mailman.qth.net>
Sent: Saturday, December 22, 2007 12:38 PM
Subject: Sudden erratic power/high current problems with K2


> I'll try to keep this short.  I was operating with my K2/100 with KAT100 
> today and everything was fine.  I changed bands and initiated tune on the 
> KAT100 and it did not operate properly.  The SWR leds went a little 
> bonkers and it did not want to settle on a low SWR.  I disabled it by 
> going to CAL and then I noticed that even though the K2 power meter was 
> showing about 2/3 scale I was getting full output on my outboard SWR 
> meter.  I then took the KAT100 out of the loop by disconnecting it fully 
> from the K2.  Now I am seeing very high power output of around 140 - 150 
> watts on the lower bands such as 160, 80, 60, 30, 40 and 20 with more 
> normal power output on the upper bands but I'm still seeing high current 
> indication on all bands.  In addition the power control on the K2 is not 
> working in a linear fashion. As I increase it from the lowest setting it 
> is OK until the KPA100 kicks in when it suddenly goes to full output.  I 
> have not ever seen this happen in the 15 months since I built the rig or 
> in the 2 weeks since I built the KAT100 - everything has been fine.  Now 
> all of a sudden I have all this erratic behavior.  As I said I added the 
> KAT100 2 weeks ago but there have been no problems at all until now.
>
> Any and all help/suggestions are very welcome!!
>
> 73,
> Bill NZ0T