[Elecraft] Unstable KPA3-100W

[James Sarte]

Hi Tom,

Have a look at the following technical bulleting from Elecraft:

http://www.elecraft.com/K3/mods/K3%20Technical%20Alert%201.pdf

Does your KPA3 have capacitor C3 installed? If so, that may be your problem.

73 de James K2QI

On Mon, Nov 15, 2010 at 9:50 PM, K5RC <tom at k5rc.cc> wrote:

> I got a number of reports from SS CW of spurious signals. I have isolated
> it
> to one K3 (S/N 4498). With the KPA3-100 disabled (below 12 watts) the
> signal
> is clean. From about 13 watts to 90 watts, there are spurious signals about
> every 1KHz  + and - the carrier frequency. The frequency of the spurs
> changes as the power control is advanced and the signal becomes clean again
> at about 90W. This happens on 80, 20 and 10 (the only bands this radio has
> antennas for). Also, the power output is unstable on the wattmeter and the
> SWR apparently changes continually indicating a wandering spur.
>
>
>
> Any ideas?
>
>
>
> Tom Taormina, K5RC
>
> The Comstock Memorial Station, W7RN
>
> Virginia City NV
>
> http://k5rc.cc
>
>
>
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-- 
73 de James K2QI
President UNARC/4U1UN