humminbird 727 problems

[mattwebster24]

I just got a humminbird 727 sonar. Whenever i turn it on it just reads 3.5 feet. yesterday i had it working for about 2 minutes than back to 3.5 feet. it reads the water temp the same as my other sonar does ut not depth. i tried fiddling with some things but can't get it to work. any help would be greatly appreciated. thank you.

[Joby@Humminbird]

Go into the setup menu and restore factory defaults. See if this correct the problem.

[mattwebster24]

i did that and it still reads 3.5 feet all the time