Same issue as last time, the depth is blinking 68 to 65 ft constantly when I'm in much shallower water. On my other unit the problem was the battery was not good. It was only getting 9.6 volts. This time I am getting 12 volts. I have restored the defaults and still same thing. This is a brand new unit I got for christmas and just now getting around to putting it in. I am using the ducer on the terrova. The believe the model is 799 but will make sure later. Any suggestions? It's driving me crazy