[Elecraft] K3 fails 5W and 50W TX calibration

[Edward Seeliger]

Today I tried to perform a K3 TX calibration using the K3 Utility and it fails calibration at the 160M (first frequency in the series) attempt on both 5W and 50W settings. It freezes and remains with the TX light illuminated. The power button will not turn the radio off. I must unplug the rear power connector to turn it off. After reinserting the power connector the power button and all other controls appear to work as they should until I again attempt a TX power calibration. The radio is in Normal not Test mode.
I have sent a message to elecraft support but thought others here might have had a similar problem and might have a solution. 
The K3 is a s/n 6000+ K3 with all suggested hardware upgrades and current firmware.
Why did I attempt the TX calibration - I read the recent suggestion about not setting the PWR to 5W - I use this K3 to drive a high gain (low power input) linear and probably have at times set the drive to around 5W.
Thanks for any help or suggestions.
Edd - KD5M