I just installed a Terrova with iPilot. I have a HB 788CI on my console and it appears to have interference. Wasn't like this until after the ATM installed. I attached a couple of photos of awat's happening.

If it is interference from the TM, is there a way to fix it? I seem to remember this being discussed before but since Search is down, I can't look for it. Any help is appreciated.

http://i864.photobucket.com/albums/ab202/rmeado1/Interference/S00011.png

http://i864.photobucket.com/albums/ab202/rmeado1/Interference/S00010.png

Mine is the same way, tried twisted pair wire and rerouting it away from the trolling motor wire but still the same. Did you say this is on your console unit

Here are some tips:

1) Never, Never Run the Transducer wire down the steering cables. This is the easiest way to induce RF Noise in the Sonar System. Here is how I run down the bracket on my Fortrex



2) Keep Sonar Wires Away from Trolling Motor Power Cables.

3) Do not Coil Excess Wires in a circle - figure 8 them.

4) Check the Fuse on the Ground Wire to make sure it is not blown.



5) If these do not help call HB Customer Service for a noise reduction powercable if your unit did not come with one

6) May need to added ferite chokes on Transducer Cable to kill noise.

7) Humminbird offers a Power Choke that installs in the power cable of the trolling motor as near the foot pedal as possible to kill the RF Noise generated from Pulse Modulation Controls in Trolling Motor. http://store.humminbird.com/products/323062/TMC_1

If you continue to have concerns contact the Graph Manufacturer and work with them to control RF Noise getting in your sonar system. Humminbird Customer Service 800-633-1468

Doug,
I too have this problem. I have done all of the above with the exception of the fuse in the motor head. My 24v Maximizer doesn't have one. Once the front one(997csi) the back one(997csi) does the same. I have a power choke on it also. I have the cord in figure 8.
I sent my unit back to Rhonda and it checks out. Any other suggestions?

Hey J, do you have your graph hooked to your TM batteries? I read a post on another forum and it was suggested to hook the graph up to the cranking battery instead, IDK if it worked just something to try I guess. So the ole Twisted pair wire trick didn't pan out......bummer!

Do you have noise reduction choke? That is the biggest thing that make a big difference and knocks out most if not all RF Noise from the trolling motor. Other thing is to run a ground wire from under hose clamp of transducer to the "-" side of the power connection.

After Humminbird sent me the TMC-1 choke for my Terrova power cable, I still had interference. Futher debugging and testing showed I also had interference coming from my GPS puck. Humminbird sent me a choke for my GPS.

Thanks for all the feedback. Guess I'll try the TMC-1 choke first and see if that does it.

Doug mentionedferrite chokes on the transducer cable. Is that different from the TM choke?

I have the US2 sonar on the unit - do I need the transducer choke?

Make sure to run a seperate circuit from depth finder to starting battery and that will fix the problem most of the time.
Johnny

I've got both my depth finders wired direct to the starting battery. The TM is the only thing running off the deep cycles.

I'm going to try the TM choke and see if that does it. I think I already had some interference from the previous TM, but it wasn't so bad as to need fixing.

Thanks.

ps - how are the sand bass looking on EM? I see you got a bunch Sunday. Do you think that was a fluke or are they ready to start biting?

Being unschooled in matters electronic, I wouldn't have thought it possible, but I have found that my MK trolling motor causes interference on my console mounted HDS, even though the only thing connecting the trolling motor and electronics battery is a wire from the onboard charger. I have to disconnect this wire before using the trolling motor.

Oops, "battery" = "batteries".

P.M. Sent Richards.
Johnny

Check out this information to learn more good information!

http://www.biggeorgiaspots.com/boats-and....html?showall=1

First a couple of disclaimers. My system is a MG TM and Lowrance HDS system, however the underlying causes of interference are not brand sensitive. Second, no guarantees --- it worked for me but may not work in all cases, however still worth consideration.

My problem showed up when I upgraded my electronics to the Lowrance HDS system. The problem was present BOTH on 2D sonar and the Lowrance Structure Scan system. I had tried all of the usual fixes that can be read about in many places on the Internet --- all to no avail!

I contacted MG and asked for help. They decided to replace the lower unit on my TM with their most current version in spite of the fact that my TM was a few months out of warranty. After the motor replacement, all 2D sonar interference was gone, however the interferfence in the Structure Scan display remained.

Next I installed a ground wire connected to the MG head unit case (and by extension to the shaft and lower unit housing). I then traced the wiring for the sonar unit power back and found the place where the sonar unit power was connected to the boat wiring (note this IS NOT electrially the same as the posts of the cranking battery). I connected the TM ground wire that I had installed to the SAME EXACT POINT that the sonar unit power was connected. Viola - no more interference!

Note that MK users would have to connect the ground wire directly to the TM motor housing due to the composite (non-conductive) shaft used on MK TMs.

Hope this is useful to someone!

C.