One for Humminbird greg

[sticksteer]

I posted a question earlier about my 728. After futher inspection I have found that when you turn it on you can feel the transducer pinging but no depth shows on the screen. It will ping for about a minute then it stops pinging and the depth displays anywhere from 700 to 1190 feet . I have checked the transducer cable and it is not nicked or crimmped and it is no where near any kind of power. I have set it back to default mode with no change. Help!! Is it the transducer or the head unit ?

[striperking]

Alot of times when you turn your unit on out of the water you will get false readings on dept.Transducers do burn out and if yours is pinging sometimes and sometimes not,I would say it is bad.Does it do this at the lake?Can you put a jig down 15FT in the water and see it on your graph?But you said it shows no depth,does it do that at the lake or just on cement?

[sticksteer]

The first time i used it it worked fine. I pulled up the trolling motor and moved to a new spot on the lake. When I put the trolling motor down it was reading depth erratically and the bottom started showing up as vertical lines then it stopped showing the lines or any type of bottom. It was after that it would not read below 600 feet.

[striperking]

Are you running 2 units? Is this transducer mounted to trolling motor if so check for pinched or frayed cable.

[striperking]

I read your first post and it sounds like your getting interference from your TM.

[sticksteer]

whats the easiest fix for an interference problem ?

[Humminbird_Greg]

Sticksteer,
Sorry for the delay in replying. I’ve been tied up at work and home so have not been back on this board in a while.

Without testing your 728 on another boat that has a Humminbird transducer, there is no way to tell if the problem is in the transducer or the unit itself. If you cannot test your unit on another boat that has a Humminbird (almost any model Humminbird will do for the test) try calling the Humminbird Customer Resource folks about getting your unit and transducer sent in for testing. 1-800-633-1468

If the problem only shows up when you are using your trolling motor that is a different matter but it should clear up when the trolling motor is not running. Call the Humminbird Customer Resource folks on what to try if trolling motor interference is the cause of the problem.