[Elecraft] Help! K3/100 Err TXG message?

[Geoff Cottrell G3XGC]

I am getting this Err TXG message (transmit gain constant out of range) 
when trying to set up my newly installed KPA3 at the 50W level. Had no 
problems at 5W level 160m-6m gives 5W out as per manual. The K3 working 
fine at the LP level. But at 50W power setting level cannot get more 
than 9W out and get the Err TXG on all these bands. Tried EE init 
followed by restore parameters using K3 Utility prog.  No change.
When installing the KPA3, and testing the KPAIO3 interface as on p. 14 
of the installation instructions, I did not hear a relay click when 
moving between NOR and TST. Cycling the power button made no change.
I am stuck - what should I do next?

Thanks for any help.
Geoff G3XGC
K3 SN 225