need help with hbird

I have a 788cidi and starting recently everytime I turn on the trolling motor I get a lot of interference and the depth jumps around like crazy. Depth will go to 60 or 75ft when im in under 10ft of water and I get interference all over the water colum and even looks like it extends under the bottom. Turn the trolling motor off wich is a terrova and it works just fine. Works just fine with the outboard running too. I don’t know what to try to fix this so if anyone can help please let me know what to do.

I’ve got the same model. Just had it installed. My issue was interference from the big motor. Every time I started the motor it caused the screen to lock or other issues. Place that installed it said sometimes this happens and they’d have to put some additional shielding on the wires to prevent interference. Just got it back so I don’t know if it’s cured yet.

I’m having the exact same issue with my 788 that you are. Taking the boat back to the dealer in the morning, all the quick fixes I’ve been told to try haven’t worked.

Youre not powering it off the trolling motor batteries are you?

Read this:

http://www.biggeorgiaspots.com/boats-and-electronics/62-other-stuff/180-aaargh-sonar-noise.html?showall=1

Nope the sonar is powered by the cranking battery. The trolling motor power is separate from the rest of the electrical system.

With the di models you might have to use the transducer that came with the unit. I had a friend with the 1158di last year that was doing the same thing and they put the transducer on the bottom of the trolling motor and then it worked fine.

The first thing I would do is to make sure the trolling motor has the ferrite ring is on the power wires off of the board of the trolling motor. The next thing to check is to see if your power cord has the choke on it. If you look at the power cord and it has a big round nob close to the unit then it is choked. Those are the two most common fixes I’ve seen on these units.