[Elecraft] K-3 ERR TXF issue

[Jack Berry]

Just had the radio for a few days, it was factory assembled and is almost new 
but I am the second owner. It worked fine for a few days then I starting seeing 
this error message (ERR TXF) when using the ATU and now get it everytime I try 
to transmit. 

I checked the FIL settings for the 3 positions occupied and it seemed they were 
good. Finally, I reset the radio back to defaults and still no success.
Any suggestions appreciated.

Jack,
WE5ST