[Elecraft] K3 Not Sending Data

[W1UE]

My K3 has stopped sending data.

If I use N1MM, I can change the radio band/mode thru the program.  If I 
change the band or mode at the radio, it does not communicate the info 
to the computer.  After about 30 seconds, the "Radio Not Responding" 
error box comes on.

If I use the Elecraft K3 Utility and poll the radio, the program shows 
"Serial Port Com3 is Open", and "K3 Polling" on the next line, but after 
15 minutes there is no info from the radio.

Suggestions?

Dennis W1UE