Posted by
Jonathan Taylor, K1RFD on
Jan 04, 2020; 3:15am
URL: http://elecraft.85.s1.nabble.com/KPA100-Hi-Cur-tp7657583p7657594.html
Don,
Thanks for the tip -- that was exactly it. I checked and replaced D16
and D17 and all is well now. (Both were showing the same voltage drop
in both directions.) I gather from your description that the built-in
wattmeter forms a negative feedback loop with the power adjustment.
My diodes and I are definitely static-challenged -- I have had a
similar problem at least twice in the KAT100 despite my best efforts
to remember to disconnect the antenna after operating.
73
Jonathan K1RFD
On Fri, Jan 3, 2020 at 10:44 AM Don Wilhelm <
[hidden email]> wrote:
>
> Jonathan,
>
> The normal cause of that HiCur message is a failure in the wattmeter of
> the KPA100. Re-alignment will not help.
>
> To test for that possibility set the power knob for about 50 watts,
> connect an external wattmeter and a dummy load. Then go Keydown and see
> what the actual power output is. If it is in excess of 100 watts, then
> that is proof that the KPA100 wattmeter has a problem.
>
> The most common cause is that the diodes D16 and D17 have been damaged
> by static from the feedline, so replacing D16 and D17 is the first step
> in attempting to correct the problem. Check again for actual power
> output with the power set for 50 watts after replacing those diodes.
>
> If you still have a problem after replacing those diodes, I can help
> with further troubleshooting.
>
> 73,
> Don W3FPR
>
> On 1/3/2020 9:15 AM, Jonathan Taylor, K1RFD wrote:
> > K2 #2462
> >
> > I just upgraded the KPA100 from Rev A to Rev D, and installed the
> > upgraded shield, under the philosophy of "better late than never" :)
> >
> > I am noticing two problems, when connected to a 50-ohm dummy load:
> >
> > 1) In TUNE, the display briefly shows "Hi Cur", followed by a strange
> > power/SWR indication such as "7 5.0-1"
> > 2) At any setting above 10W, the Power knob seems to have no effect --
> > the wattmeter always reads approximately 100W output. This is true
> > both in TUNE and in CW.
> >
> > The actual power output appears to be about 100W, when measured with
> > an external wattmeter (although a bit low on 10M).
> >
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