[Elecraft] odd happening with KPA500

[iain macdonnell - N6ML]

Tony,

Have you tried running through the TX gain calibration on the K3? It
may be overshooting on key-down....

    ~iain / N6ML


On Mon, Feb 6, 2012 at 4:39 PM, Tony Estep <esteptony at gmail.com> wrote:
> My K3 and KPA500 have lived happily for months, ever since their first
> blissful night together. But today something bizarre happened, and I'm
> just wondering if anyone else has seen this:
>
> I had a couple of QSOs on 15 meters, with everything working FB as it
> always does. But then a little later when I tried to call a DX station
> on CW, the amp faulted, claiming PWRIN HI. I reset it, verified that
> the power in was 30W, and tapped the key. Same result.
>
> Then (here's the bizarre part) I reset it, pressed TUNE, and advanced
> the power from its normal tune level of 8W up to 30W; the amp put out
> 500W, no problem. Then I set the K3's transmit output power to 3W and
> tapped the key; PWRIN HI fault.
>
> So in other words it tolerated 30W of drive if I applied it via the
> TUNE button, but not even 3W of drive in normal transmit.
>
> I checked the antenna, the grounding connections, and everything else;
> nothing had changed from the configuration that has been working
> perfectly on all bands for months. Then I tried the amp on all other
> bands, 80 thru 10. All operations perfectly normal.
>
> Finally I powered off the amp and switched the rear 0/1 switch off,
> and fired it up again. 15 meters returned to normal, and all is well.
>
> My guess is that that the PIC chip is addressing some volatile memory
> where intermediate values are stored, and a memory location pertinent
> to 15 meters only got scrambled by something. But that's just a guess;
> actually, I dunno what happened, but I sure hope it doesn't happen any
> more. Anybody have any thoughts?
>
> Tony KT0NY
>
>
> --
> http://www.isb.edu/faculty/facultydir.aspx?ddlFaculty=352
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