my 787c sonar is not changing ranges andis not indicating the correct depth digitally(reads 1.6 ft all the time) but the sonar reads the graph very weakly. It is stuck on 0-10 ft scale . I have tried to reset the defaults with no help. Could the transducer cause the sonar to do this? Gps and other features work fine. When I tried to increase the range manually the signal was very weak.
Any help would be appreciated. Larry