Ladies and Gentlemen, I have a X-15 unit and I have noticed a couple of issues with the sonar portion of my unit. From time to time, it will display a dept of 0, and not show a darn thing as far as fish. I can understand the no fish portion, but I know I have water below me, and have verified it is at least 5' deep. The unit does not "Freeze Up" as I define a "Freeze Up", just doesnt display anything. GPS portion works fine. I upgraded to version 3.1, same thing. Called Lowrance, and the guy told me that he did not know of any issues, as reported in a earlier post I read a couple weeks ago. His suggestion was to buy a new transducer and test it to see if it is the problem. Any other suggestions? Thanks, Travis