Helix 7 Motorguide interference

Ok guys I posted this in the other section on Humminbird and got crickets.. I have a Motorguide X3 24v with a Helix 7 DI on the bow. It’s great till I hit the power button on the trolling motor. Then the depth goes to 1000+ feet and the screen turns red and yellow. I have read for hours on this. Lots of people have the issue and some have resolved it. I ran a power supply straight off the battery to the graph. No trolling wires are near it. I grounded the trolling motor head to the negative post of the battery. Still got the interference. I ordered two ferrite filters to install this weekend but have read those don’t always fix the issue. Does anyone really have a fix. A lot of the stuff I’m reading is a couple years old.

Coolarrow,
I have an Xi5 and 'bird 856HD on my bow. I had really bad interference just like you when I first got the TM. I did all of the things you listed.. I was powering the finder off of one of the TM batteries, moved that over to my cranking battery and connected the negative of the crank battery to the negative of the first battery in the 24v series string. 2nd.. I got one of the power cords with the ferrite core in the power cord.. that does make a huge difference. Lastly, I don't have the tranducer cable attached to the TM anywhere. I have the humminbird transducer mount for mounting to the TM, and I did use electrical tape to direct the transducer away from the TM. My interference has just about gone away. I do have the filter turned on on the 856, but I think its on low. The way the Xi5 is made, the shaft passed through the motor that rotates the TM.. and to deplore it the shaft slides through the center of that motor, so its not possible to attach the transducer cable to the shaft of the TM. I watched a few youtube videos about installing the Xi5, and everybody said to wrap the cable around the shaft 4 times, to keep it close to the TM but that proved to be a big source of interference for me. I ran the cable through the TM mounting lock, just to keep it close to the TM but it stays about 10" away from the TM all the way into the boat. The extra transducer cable I have also rolled into a coil that is stashed in my anchor locker under the 856. I don't know if it makes any difference at all but coils tend to have a high impedance to high freq. noise sources.. Good luck with your install, I think that power cord with the ferrite filter in will help a lot and also getting the ducer wire away from the motor will also.
BD

Thanks Bill I’ll add the filters and see what happens. If no help I’ll try the ground between the battery’s, I really hope I find the smoking gun. Probably got 20+ hours into the hunt. I can’t believe the manufactures aren’t all over this after reading all the stuff online!!

CA... before I got the ferrite choke power cord, I tried everything I could think of just like you did. I put some braided shield over the power cable and tied the end of its toward the power connection to the ground of the battery. I think that helped some, but for sure didn't work near as well as the ferrite choke. Really, between adding the choke and keeping the transducer cable as far away from the motor as possible was the best.

Thanks again! I’ll post the results after I get everything done.

Ok. I got it!!! Dedicated power wires off the cranking battery, did not fix it. All wires away from the trolling motor power cables, Did not fix it. I tried running a ground wire from the hose clamp that holds the transducer on to the negative post of the cranking battery, did not fix it. I ordered two 1” ID ferrite cores off Amazon and I ran the transducer wire through it 6 wraps just below the head unit. I also did the same with the power cable. I drilled the skeg of the trolling motor and tapped it to 10/32. I moved the ground to there. So it runs from the skeg to the negative post of the cranking battery. Then I updated the software and the mapping on my unit. Zero interference! I know everyone said to do this one step at a time so you know what fixed it but I don’t care which one did! I am just glad it fixed. I feel like the manufacturers of this high dollar equipment should be trying to resolve most of these issues before it hits the public but oh well. I know you can read articles and watch videos till your sick on the subject! I did but it finally paid off.
And thank Bill for your feed back!! I really appreciate you responding to my call for help!

Well 15 minutes on the water today and it problem came back. I can swap my units out and the console unit works fine on the bow so I got a bigger issue with the head unit..

CA... I bought the humminbird power cord with the choke molded into the cable, and that was the way I went. Interesting that you bought the cores off of amazon, I tried some cores I bought at a hamfest and put them in the power connection but they didn't make any difference. Those cores have a specific range of frequencies that they have an effect and I didn't know what mix the cores I bought were.
Also interesting that changing out the units helped. What is the distance between you DF and the TM head when deployed? I wonder if that interference is coming directly and not via cable at all!

good luck
BD