[Elecraft] KPA500 power fluctuations

[Dan Maase AC6DM via Elecraft]

I've observed metering fluctuations as well.

Equipment:  K-line.
ALC off
Operating mode:  Amplifier output direct to dummy load or antenna -- same
observed behavior with either load.
Constant power, e.g. CW
All cable verified as good.

1.  KPA500 LED Power Indication -- In standby or operate, the last power LED
flickers.  In Standby, at any drive power, the last power LED flickers.  In
Operate, at any drive power, the last power LED always flickers.  
2.  KPA500 SWR metering -- always stable
3.  KPA LCD Analog power metering -- In standby, the meter is stable; i.e.,
with 100 watts drive -- indicates 100 watts.  In operate, at any power
level, the analog meter fluctuates.  The amount of the fluctuation is
difficult to discern since it varies rapidly.
4.  Peak Hold -- when in Peak Hold mode, the last power LED's are stable,
but occasionally in Operate, the next to last LED flickers.

K3 metering stable.

When monitoring the K3 or KPA power output on Elecraft W2, the power
indication is stable.

Question:  Is this a KPA500 metering anomaly?  Or is this an indication of a
power supply noise problem, e.g., power supply hum?  No one has complained
of hum.  I did get one and only one comment from a discerning individual
that there was audio break-up at peak modulation.

I've not yet rigged up a scope on the PS, pending comment from others.

Dan
AC6DM



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