Transducer problem or unit itself?

[triplecurl]

I've have a Humminbird 597ci that is around four years old. The other day I turned it on, launched the boat , and it was reading the depth and all correctly. Shortly thereafter, it started giving crazy depths like 400 and 500 hundred feet and the sonar quit reading as well. Everything else works. I spoke with Humminbird and all they could tell me was that I could send it in and they could diagnose it. I've never had a transducer or unit mess up on me. Does this sound like a unit or transducer problem? I'm hoping it's just a transducer.

[NuffDaddy]

Transducer would be my guess. If the unit was bad you would have a messed up picture I would think.