[Elecraft] KPA500 Faulting on high SWR on power rise

[Logan R Zintsmaster]

I’d guess that something is going on in the tuner. Maybe a leaky gasket and some corrosion. 

Logan
Sent from my iPhone

> On Feb 23, 2018, at 10:00 PM, GaryK9GS <garyk9gs at wi.rr.com> wrote:
> 
> Hi Chris,
> Unless there is something arcing, I would guess RF getting into something.  Maybe the control cable to the auto tuner?  
> 
> 
> 73,
> Gary K9GS
> -------- Original message --------From: Chris Hallinan <challinan at gmail.com> Date: 2/23/18  11:42 PM  (GMT-06:00) To: "<elecraft at mailman.qth.net>" <Elecraft at mailman.qth.net> Subject: [Elecraft] KPA500 Faulting on high SWR on power rise 
> Greetings from southwest Florida.
> 
> My KPA500 is kicking out with REFL HI warning (high SWR).  But here is the
> strangeness. My setup is K3->KPA500->40' coax->MFJ 600W remote tuner -> 4:1
> balun -> open wire feedline to 80-meter doublet.  In words, I have a remote
> autotuner feeding an 80-meter doublet fed with 600-ohm open wire line.  A
> Balun Designs 4:1 balun provides the interface from the open wire line to
> the tuner.
> 
> With the autotuner tuned at low power, the SWR shows 1.5:1 on my KPA500 and
> external SWR meter.  As I run the power up to 300, 400, 500 watts,
> somewhere in there all of a sudden the SWR instantly jumps off the scale,
> into the red LEDs on KPA500, and it faults.  It's as if the SWR were
> dependent on power.
> 
> Even stranger, when I back the power off to say 250 Watts, holding key down
> the SWR is stable in the green (<1.5:1), but when I key it at CW rates, the
> SWR bounces into the red on every dit and eventually faults, when at steady
> state key down it never leaves the green zone!
> 
> I fear it is the tuner falling over, but it should be able to handle the
> power.  I see this on all bands from 80-20.
> 
> Operating into my 20-meter resonant vertical, with no tuner, everything
> works fine.
> 
> Any ideas or hints on how to correct this?
> 
> Thanks,
> 
> Chris
> 73 de K1AY
> 
> 
> -- 
> Life is like Linux - it never stands still.
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