[Elecraft] K1: KAT1 -- cannot reach 5.0W output when adjusting R1 after calibrating power

[Mark Lampert (KB3OKS)]

Has anyone run into this problem when finishing up their KAT1 ATU? I
was unable to find similar descriptions here.

I built the RF probe in order to calibrate power with the KAT1 and
have verified that the probe matches the schematic described in the K1
manual. Following the steps in the KAT1 manual, I set the ATU menu
entry to CLP (calibrate power) and then exit the menu, set output
power to 5.0 watts, set the K1 to use its lowest band (40m in my
case), and check that R1 and R2 are set to 60% of their travel (about
1 o'clock).

RF probe tip taps the center conductor of my 50 ohm dummy load, and
the negative is clipped to the dummy load's chassis.

After entering tune mode, I'm able to reduce power with WPM - (it
starts out reading about 24 VDC) until I reach about 14.0 VDC on my
DMM as described in the manual.

[The problem:]
The power out display on the K1 is now showing about 1.0. Adjusting R1
even all the way to its max will only display 3.8 at the point where
R1 is maxed out. I'm unable to reach 5.0. If I then exit tune mode and
check my power out setting in the OUT menu setting, it's down around
1.0, plus or minus a few tenths.

Has anyone else experienced anything similar? I've re-read everything
but can't seem to find a missing link.

Thanks very much and 73,

Mark / KB3OKS