[Elecraft] "Hi Cur" Display Reading on K2

Wed Sep 10 10:34:01 2003

Paul:
  Your current will rise under tune as the K2 tries to achieve the 
requested power (and, under prolonged use of tune, as the finals heat up). 
Also, I'm not sure what sort of dummy load you are using, but if it heats 
up under the kind of power you are feeding it, the load could be changing, 
further causing problems.  In any event, you are best advised to keep in 
the tune mode for short periods only (a few seconds).

  Meanwhile, be advised that the 2.5 high current limit stipulated in the 
manual is extremely conservative.  Once you have evidence that your K2 
seems to be behaving properly (is doing essentially what it should without 
smoking, choking, or barfing), you can increase the high-current limit.  I 
think people usually end up around 3.25-3.5 amps.  This is reasonably safe 
when going into a good load.  [I believe Elecraft recommends 3.5 amps, for 
example, when the KPA100 is in line.]  That's basically where I put my K2 
when run barefoot and all was fine.  Just be vigilant until you have reason 
to trust.

best wishes,

dave belsley, w1euy

--On Wednesday, September 10, 2003 12:35 AM -0700 Paul Clay 
<[email protected]> wrote:

> Hello all!
>
> Just finished all but the final assembly of my
> (basic - no mods yet) K2.  During the alignment
> process, everything went A-OK (including the
> measured current draw at 10 watts, performed per
> the manual at the end of aligning the 40 meter
> stage of the transmitter, which I found to be
> 1.92 amps).
>
> When I completed the alignment, I thought I'd see
> check to make sure I was getting plenty of power
> out on all bands (b/c some have written of lower
> output in the upper bands). Here's what I found
>
> I get plenty of output on all bands, but notice
> that  on 12 and 10 meters that when I set the
> power for 10 watts and hit TUNE, my current
> reading (on the K2 display) will start at just
> under 2 amps, and over the next 3-5 seconds then
> gradually increase to 2.5 amps after which I get
> a Hi Current message.
>
> I'm using the dummy load built into an MJF
> Versatuner II attenna tuner to absorb the
> transmitter load while checking the transmitter
> output.  The Hi Current reading only arises when
> I'm bypassing the antenna tuner circuit and just
> feeding the power into the dummy load.  If I run
> the transmitter signal thru the tuner's tuned
> circuit and into the dummy load, the current
> maxes out at 2 to 2.3 amps and the Hi Cur message
> never displays.
>
> I'm figuring that the Hi Current reading isn't
> indicative of a problem with my K2, but rather
> with the dummy load maybe not being a purely
> resistive load (cause, no problems on the lower
> bands, plenty of output on all bands, the
> displayed voltage never drops below 13.1v on
> transmit (it's 13.4 on receive), and the problem
> disappears if I run the output thru the antenna
> tuner's tuned circuit).  A bad call/miss
> diagnosis?  Or could there really be a problem
> with the K2.
>
> - Paul (ser 3640)
>
> P.S. The K2's connected to the tuner/dummy load
> via a 6 foot piece of RG58U coax, and I'm using
> an Astron switching PS rated at 13.8 volts at 12
> amps.
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----------------------------------
David A. Belsley
Professor of Economics