[Elecraft] K3 power output problems

[Mark n2qt]

On a new to me K3, I am having problems with power output below 15M.   For 
example
the power output on 80 maxed out at 30 watts.  (good swr etc., no alarms, 
voltage input
is good etc.).

So figured it was a TX gain issue so set up recalibrate it.  The 5 W 
calibration goes fine
on 160, but fails on 80 with the following dialog

Starting 5 watt calibration
Calibrating at 1.900 MHz
Calibrating at 3.750 MHz
SWR 3.7-1 is too high for calibration
Verify that a dummy load is attached to "AN2;"

(and yes the dummy load was connected to AN2,  I had previously tried it on 
AN1 with the
same results.)

If I then transmit manually, the SWR indicated is 1:1 and I can adjust power 
up to the same
30W indicated previously.

So, the TX calibrate complains of high SWR, but manually cannot replicate 
it.

Any ideas (really, really) welcome.

Unit does have the AntTuner which is set to bypass (and it looks like the 
calibrate routine also
does this.)

Mark n2qt