[Elecraft] KAT2 Hi Cur warning

[AE0MM]

Just installed the KAT2 in a newly assembled K2. At power levels greater than 8.0 watts, the K2 was displaying the high current warning. The KAT2 power calibration was calibrated by measuring voltage with the K2's RF probe at the feed point to a dummy load.

I removed the KAT2 and remeasured the power across all bands. Again, power was calculated based on DC voltage from RF probe at dummy load feed point. The impedance of the feedline and dummy load were retested. (49 to 51 ohms over the amateur radio bands, measured with a sark-110 calibrated using a set of reference loads)

Here are the results:

Band    Power At Load   K2 Current
80      9.7     2.2
40      9.2     2.0
30      9.4     2.1
20      9.7     2.1
17      11      2.1
15      9.3     2.0
12      9.4     2.2
10      9.6     2.3

After remeasuring power, the KAT2 was reinstalled, and its power meter verified correct at 5 watts. With the KAT2 reinstalled, rechecked K2 current draw at 10 watts on all bands. For each band it measured 20% to 30% higher than without the KAT2.

With the power level on the K2 set to one watt and the ATU set to CALP, I used the RF probe to measure a few points on the KAT2 control board, and the input from the RF board. At the one watt level, there is approximately 1v drop between K17 pins 2/9 and 4/7.

K17
Pins    Volts
2/9     9.9
3/8     9.9
4/7     8.6

K18
Pins    Volts
3/8     8.6

Is this expected behavior, or is something amiss with this KAT2?

Thanks,
--mark/ae0mm