[Elecraft] KPA500 output on 6 meters

[Robert Friess]

Hi Pete,

It sounds like a hardware problem in the low pass filter module.  Contact
Elecraft customer support.

73,
Bob, N6CM

On Tue, Dec 11, 2012 at 10:11 AM, Pete Lascell <plascell at verizon.net> wrote:

> Operating my K3 on 6 meters with the KPA500 ( S/N 1009 ) is new ground for
> me.
>
> The amp has been performing on lower HF frequencies with expected results,
> but on 50 MHz the power output into a dummy load is questionable.  If I try
> to tune with CW carrier (XMIT putton) , I can only get about 200-250 watts
> before the amp "faults" and shows PA DISS.  The HV is about 60 volts and
> current 14 amps with 24 watts drive for 250 watt ouput level before "fault".
>
> If I key CW dots or dashes, then I can increase the drive to 40 watts for
> 450 watts output into dummy load with 1:1 SWR.
>
> HV unkeyed is 75VDC, operating on 120 VAC.  (Don't remember where the
> transformer tap is)
>
> Specs seem to indicate the RF output should not degrade on 50 MHz and is
> rated for 500 watts PEP CW / SSB / DATA.  Can I assume I should be able to
> get 500 watts RTTY carrier for 15 seconds ?  I get a "fault" within half a
> second if driving it for power out levels higher than 250 watts.  My TEMP
> has never gone above 60 C.
>
> Am I doing something wrong?
>
> Do I have a hardware failure?
>
> What should I expect to be normal operation on 6 meters?
>
>
> Pete W4WWQ
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