[Elecraft] KPA3 misbehaving

[Steve Reed]

Interesting!  As far as I know the power hasn't been reversed.  Possibly,
however, that current sensor has gone south for other reasons.
Fortunately, my K3 is still under warranty, I'll be talking with Elecraft
support this morning.

Steve, AI7AZ

On Mon, May 7, 2012 at 7:38 AM, Russell Tobolic <erusst at att.net> wrote:

> Steve;
>
> I believe you have the same problem I had a few years ago on my K3 s/n
> 732.  It turns out that the current sensor IC, U6 on the KPAIO3 board was
> toast.  When you go above 12W this sensor measures the current to the KPA3.
>    There is also the same sensor (U1) on the RF board which is protected
> against reverse voltage on the 12V in.  The sensor on the KPAIO3 board is
> not protected against reverse voltage as this is connected directly to the
> input connector.  Please don't ask me how I found this out.   Could you
> have possibly reversed the 12V to the rig momentarily?  I replaced U6 and
> that fixed it.
>
> Russ, N3CO
>
>   ------------------------------
> *From:* Steve Reed <ai7az at arrl.net>
> *To:* Elecraft Discussion List <elecraft at mailman.qth.net>
> *Sent:* Sunday, May 6, 2012 3:55 PM
> *Subject:* Re: [Elecraft] KPA3 misbehaving
>
> OK, another update.
>
> I tried the PA alignment procedure with the K3 utility.  The 5 watt
> alignment goes fine.  The 50 watt alignment fails with "Hi Curr".
>
> Removed the KPA3, checked for anything obviously loose (all looks good) and
> reinstalled.  Same error....
>
> Guess this will be a call to Elecraft tomorrow, unless someone in this
> forum can help.
>
> Steve, AI7AZ
>
>
> On Sun, May 6, 2012 at 10:04 AM, Steve Reed <ai7az at arrl.net> wrote:
>
> > All,
> >
> > Here's the latest on my K3, now that I'm back from 7QP and can put it up
> > on the bench and focus on this.
> >
> > When the PA setting is set to "normal", I can in fact hear the relay
> click
> > when I turn the power control past 12 watts.  However the display keeps
> > indicating "Hi Curr" and kicks it all back to 12 watts or lower.  As you
> > turn the power knob up, you can see the power setting increase, but "Hi
> > Curr" keeps flashing in the display.  This is all *without* the K3
> > transmitting.  Go into transmit mode and all you get is definitely 12
> watts.
> >
> > The serial number is 5662.
> >
> > I plan on calling Elecraft about this tomorrow.  In the meantime, anyone
> > have some ideas?
> >
> > Steve, AI7AZ
> >
> >
> >
> >
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