[Elecraft] KX3 Intermittent changes in audio gain

[Matt Zilmer]

The KX3 probably detected a HI CUR condition.  This can happen because
of high (or low) PS voltage due to automotive electrical fluctuations.
Sometimes this can happen because of ground current with the antenna
connected, so check this for a positive correlation.

You should not see HI CUR while on the KX3's internal batteries.  This
proves the automotive supply is caused it.

When the KX3 sees HI CUR (usually something higher than 300 mA on RX),
it will flash that HI CUR message on VFO A.  If the condition
persists, it will drop the AF gain to some predetermined value.  If
the condition continues beyond that point, the KX3 will shut itself
off to protect itself.  In my own case, both the AF gain and
self-shutdown events were happening.  HI CUR is preventable in a
mobile setting - see below.

I produced a pretty good document on KX3 mobile ops, which I'm about
to add to.  It's posted on the Elecraft web site at
http://www.elecraft.com/K2_Manual_Download_Page.htm#kx3_mobile.

Keith, I saw that same type of problem while mobile with KX3 #6 right
up until I installed a DC-DC converter.  See the doc for details of
all that.

73,
matt W6NIA
KX3 #6, K3 #24, etc.

On Fri, 21 Sep 2012 05:45:18 -0700, you wrote:

>I had this happen to me during mobile operations and not sure why either. Signals dropped right out and then when I turned off the radio for a few minutes and when i turned on the KX3  it went back to where it was prior and remained that way.
>
>I will keep an eye on it to see if it happens again. 
>
>Keith
>AG6AZ
>
>Sent from my iPhone please excuse typos
>
>On Sep 20, 2012, at 7:43 PM, "Kevin Luxford" <elelist984 at elitemail.org> wrote:
>
>> Hi Guys,
>> My KX3 has just developed an apparent fault - the audio level changes 
>> abruptly every few seconds from a comfortable listening level to quiet, 
>> but still audible.
>> 
>> I am using my Proset headphones.
>> 
>> Any thoughts on where I should start looking?  I am nervous about poking 
>> around surface mount circuits!
>> 
>> vy 73
>> Kevin
>> VK3DAP / ZL2DAP
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