Topic: Got the Dreaded Trolling Motor interference

[nmanley]

Moved my 798c (stock SI xducer) up to the trolling motor since I installed the new 898c on the console.
Got on the water for the first time today and I have the interference every time I'm on the trolling motor and have side imageing up. Down scanning seem to be not effected.
I have no chokes or other interference countering item installed other than the stock power cable's built in filter.
Tolling motor is 36V Motorguide.

Guess I'll cal HB tomorrow and see what the solution will be to start with.

[Wayne P.]

Good luck with that issue. I have the TM choke, and the supplied power cable with choke. I also installed 2 chokes on the transducer cable that I purchased from Radio Shack. I have the Motor Guide Tour 36V also and grounded the foot pedal to my metal boat hull along with a jumper from the ground to the negative power wire, The negative at the batteries is grounded to the hull, still got interference.
I get the interference even if I hook the power up to a dedicated battery located within the power cord length and add an additional co-ax choke on the power cord.
I've run out of ideas.

[nmanley]

Hi Wayne, Thanks for the info. Is it causing problems with all modes of operation or just the side imaging , like mine?
In Si mode the screen scan goes to a solid bar across the screen for the duration of the trolling motor running.

Did you get the newer transducer that some are talking about? I understand it's like the one used on the larger units but with extra shielding built in to the unit.

[Wayne P.]

nmanley, I only see the interference on the SI view. It may show on the DI view but I haven't noticed it. I get the streaks across the screen on both sides when the speed setting is any other than max. I get no interfence at max speed setting because the electronic speed control is not used with that setting.
No, I did not get the HDSI transducer when I received the TM choke. I am using the trolling motor stype transducer XTM 9 SI 180 T.
I read about the " shielding" inside the HDSI and tried a piece of copper sheet metal between the transducer and motor with no effect.
I sent an e-mail to the service dept this morning asking why I did not get a reply from my e-mail of April 16th letting them know that the TM choke had no effect on the interference. Also I asked about my attached note (describing all I had tried to eliminate the interference) a little over week ago when I sent the unit in for a display defect and only the defect was acknowleged and repaired.

[Humminbird_Greg]

Wayne P., call into the Humminbird Customer Resource Center folks at 1-800-633-1468 and ask that one of the shielded transducers (with the correct hardware) gets shipped out to you to try.

[Wayne P.]

Thanks, Greg, I know from several attemps it is useless to call on a Monday.
I'll just wait a week or so for a reply of my e-mail. I know they are busy and am glad they are. I'm in no hurry. The unit works great at the transom/console position.

[nmanley]

Ok, Wayne. So we have the same problems then. I am using the transducer that came with the unit and have it mounted with a Transducer Shield™ & Saver.

 

I got busy and didn't get to call HB CRC today so hopefully tomorrow I can get a newer shielded transducer sent.


Thanks for popping thru here Greg. Your attention to helping HB owners is appreciated and one reason I bought my 898c last week. 

[Wayne P.]

nmanley, maybe IF the TM interference issue is solved, maybe the shallow water issue will soon follow.
Good luck

[nmanley]

I have no doubt that HB will get this shallow water issue solved it will just take a while because there are most likely THOUSANDS of lines of code to decipher to find the problem(s) and then fix without affecting other features.  That's one major reason I stayed in Electronics rather than pursuing a Programming degree. 

The trolling motor issue is actually harder for them to cure. The trolling motor manufacturers are not worrying about EMI/EMC interference as long as it doesn't effect their own digital circuits. You would be surprised how much the government spends to test aircraft for EMI/EMC (EMV) radiation interference. 

I see shielded cables and transducers all the way to the head unit and internal shields for all units in the industry's future. All the floating grounds in a boat does not help much either. Maybe some Enclosure Simulations will help too.

[nmanley]

Just got off the phone with Jennifer at HB. Man if she looks as good as her personality is Maxium's Hot 100 has got a new #1 candidate. 

Have the new transducer and IF kit on the way.

[jseasor]

i had an issue of interference for years with my HB's and Motorguides. i was only getting interference when i get the button for the TM to go.  i tried every choke,  and trick in the book but to no avail i never fixed it...UNTIL, i talked to a guy on the phone and he fixed my problem in about 2 minutes.  i took a standard small wire, and hooked it to the positive wire on my graph, then ran the wire out and clamped it on the shaft of the TM.  it finds a common ground between the two items. it works more effeciantly if you do it like i mentioned rather than finding a common ground between the batteries. i ran my wire down and put it underneath the clamp that holds the shaft to the mount. never had any problems after that...hope this helps. if you need more help let me know..

[Wayne P.]

I can't be that simple if other measures were still attached. I assume you removed any added grounding wire connected to the negative at the batteries, correct?
A grounded postive equals a short circuit without adding a load.

[nmanley]

I can't be that simple if other measures were still attached. I assume you removed any added grounding wire connected to the negative at the batteries, correct?
A grounded postive equals a short circuit without adding a load.

That's not necessarily true Wayne. I checked my shaft to the GND and Positive side of the Trolling motor plug and there is NO continuity on my Motorguide. So basically the Positive wire to the Shaft is making some kind of resonance filter. Crazy as it sounds you can't short the system but it seems too easy to work. Now on a MinnKota this may not work as they have a ground on the newer motors casings to the Negative line.
I may try this after measuring continuity again TWICE!!!   

[Wayne P.]

I get interference even with a separate dedicated battery sitting on the front deck near the 798 with the power cord directly connected to that battery. Do you think a wire from that battery's positive to the trolling motor shaft will eliminate the interference?
Did you put a fuse in that positive wire connection or did you attach the wire to the load side of the unit positive wire fuse?

[jseasor]

That's not necessarily true Wayne. I checked my shaft to the GND and Positive side of the Trolling motor plug and there is NO continuity on my Motorguide. So basically the Positive wire to the Shaft is making some kind of resonance filter. Crazy as it sounds you can't short the system but it seems too easy to work. Now on a MinnKota this may not work as they have a ground on the newer motors casings to the Negative line.
I may try this after measuring continuity again TWICE!!!   

your exactly right! it works, ive fixed several MG and Bird interference problems like this.  it will not work if you have a built in transducer in your TM, but if its an added one...it usually works.  the common ground on the battery is usually a good fix for a minn kota, but where its a composite shaft, the grounding on the TM shaft will not work.

[jseasor]

I get interference even with a separate dedicated battery sitting on the front deck near the 798 with the power cord directly connected to that battery. Do you think a wire from that battery's positive to the trolling motor shaft will eliminate the interference?
Did you put a fuse in that positive wire connection or did you attach the wire to the load side of the unit positive wire fuse?

wayne, i did the same thing, i put a battery right up there with me and still got interference.  as soon as connected my wire it solved it..it was instant.  i think i took a 12 gauge or 14 (small wire) and just simply tapped it into my graphs hotwire, ran the wire up and taped it to the shaft of the TM.  eventually i just put it under the mount clamp that holds the TM to the mount.
OH and i did not add a fuse anywhere, i mean i guess you could but i dont see the point.
i dont think it solves all interference problems, it just depends on what type your having.  however,  ive seen this one solve as many problems as anything else. and believe me i tried everything. ran everything straight to the batteries, rewired my whole boat, chokes, new transducers, noise filter on my unit, .......

[Wayne P.]

jseasor, I added the wire to my motor and attached it to the shaft with a stainless steel hose clamp just below the head, used  the dedicated battery, and tested it today. The  interference was much worse, so I disconnected it. I just get interference on the SI view.

[Wayne P.]

I got this e-mail from Humminbird this morning about the interference issue:

Dear Wayne,

Thank you for contacting Humminbird. We appreciate your interest in our products.

We do apologize for the inconvenience that this has caused you and we do read and answer all emails that are sent in.

I assure you that our Service Technicians do read the letters that are included with the units when sent in and use the provided information to assist in the service of the unit.

After the unit has come into our service center and undergone several test to duplicate the interference issues we have not been able to find any fault within the system.

The interference is deriving from the trolling motor and it would be advised to contact Motor Guide on assistance in eliminating this interference as the unit has tested and come back clean and clear of any defects that would cause this issue.

One customer with a Motor Guide trolling motor has brought his system up here for inspection and it was found that if a ground wire is connected to the negative (black wire) of the power cable leading to the fishing system and ran to the shaft or metal housing of the trolling motor that this corrects the issue.

If we can assist you further on this subject or any other Humminbird related questions please feel free email us again or contact our Customer Resource Center at 1-800-633-1468 to speak with a Customer Service Representative. Our hours are Monday thru Friday 8:00 a.m. to 4:30 p.m. and Wednesday 8:30 a.m. to 4:30 p.m.

[nmanley]

Well I did what jseasor said by adding a wire attached to my trolling motor shaft, at the mounting bracket, and spliced it in to the RED 12V wire where my 798ci's power cord is attached. Turned on the unit, with the boat in my shop/boat house, and ran the trolling motor while in the SI mode on the 789ci. I got a very short duration spike when the motor is started but the screen clears doesn't show the bar of NOISE during the rest of the motors running. Only on the start does it show anything. I took a picture of them on my iPhone and will post it when I get home from work soon.

I think when the motor and shaft is in the water it will filter this NOISE out even better.

[jseasor]

it SHOULD be better in the water, water is a natural conductor when dealing with electric. let me know how it works out im as novice as a person can get when it comes to anything mechanical, i just know what worked for me and a few others. i really hope it works out for ya.

[nmanley]

Will do that J.

Here the picture I took in my boat house.

There are 4 white spike lines on each side of the SI image. The spike happen only when I first press the trolling motor pedal switch. Trolling Speed was set to medium level. The motor was running continuously except for when I released the switch and pressed it again.

[Wayne P.]

My inquiry to a Motor Guide Service facility was answered today.
The remedy suggested was to install a ground strap inside the shaft like those done for the Minnkotas.
It doesn't make sense because the Motor Guide shaft is all metal and should serve the purpose of the ground strap.
Opinions?

[Wayne P.]

For a comparison test of the suggested ground wire from the trollng motor shaft to the positive or negative power wire conductors, I just did this test:
The bottom lines are with no grounding wire
The middle is the ground wire on the power wire negative
The top is the ground wire on the power wire positive

As you can see the grounding causes a lot more interference

 

[nmanley]

Hey Wayne... what model Motorguide are you running.
Mine is the Digital Tour 36v. Thrust is either 109Lbs or 105Lbs. Heck if I know for sure and sure couldn't tell the difference either way.

I'm planning on hitting the local lake and check my 798ci and 898c as well as the interlink. I'm thinking of upgrading to 4.780 on the 798ci. Will determine that depending on how well the unit works on the water with current software.

[Wayne P.]

I have the older (but new-in-box-last-year) 81# 36V Motor Guide Tour Edition (medal foot pedal and lower top section).
After several e-mails from a Service Center, the "problem" MAY be in the method of variable speed control that is different from the newer 109# motors. My motor does not state "Digital" like the newer models. I can't get a definitive answer either way when it comes to diagnosing and eliminating interference. Some individual motors in either brand seem to never get resolved.

[Wayne P.]

Another thing I did "just in case" was to re-route the transducer cable. I had the cable tied to the sheath containing the steering cables and power cables from the motor head to the foot pedal ( making it look pretty, LOL). Thinking that the adjoining route may be adding to the antenna effect, I removed that routing and just brought the transducer cable from the motor mount channel to the display mount with the excess length of cable in a coil of about 4" in diameter tied about 8" from the transducer plug.  I did that before doing the interference test as shown on the previous post. No change with that measure either.
While typing this, I'm thinking my next test will be removing the transducer cable from it's route along the trollng motor shaft and just have it free with only the transducer making contact with the motor. Before I do that, I am going to remove the hose clamp from the transducer and repace it with plastic wire ties for a test.
Results to follow--------

[Wayne P.]

The continuing saga of interference:::::
First, I removed the stainess steel hose clamp and used two plastic wire ties--nada
Second, I removed the transducer cable from the motor shaft---nada
Third, I removed the transducer from the motor ---no interference--Ta-Da !!!
Fourth, I re-routed the cable from crossing under the transducer and re-installed--nada
Fifth, I held the transducer in my hand at various lengths from the motor and if it got it closer than 8 1/2", I got interference.
Now all I need to do is make a spacer at least 8 1/2" thick out of material that will not transmit RF signals.
Sounds like a plan--HUH?
I guess I could get a ground wire run inside the metal shaft , but if I get interference with the transducer or cable not even attached to the motor. What function would the ground wire serve, and what would be grounded to what that is not alread grounded with the metal shaft? All these test were with a separate isolated battery and the RF is transmitted thru air outside of the bottom of the motor housing.
Nap time------------------------------------

[nmanley]

Good luck getting the trolling motor companies to do anything like Humminbird has tried to do for us. I Applaud Humminbird for their effort in this matter and I can live without Side Imaging on my front fish finder.
Here's my pic from today. This is with the new transducer and the ground wire from the shaft to the positive wire on the 798ci.


It didn't keep me from catching this one today. 

[Wayne P.]

nmanley, I already have a mount for the 798 on my console with transom transducer and another HB sonar/gps unit at the bow that is not SI which works fine if I don't upgrade the software to get Switchfire and get the shallow depth reading problem.
I'll be giving up trying to use SI on the trolling motor. I'm not going to spend another grand for a new trolling motor hoping to not have SI interference.
That white band on your SI screen looks familiar, LOL

[RGecy]

I haven't read every single post in this topic, but I did read a post where the ground wire was being hooked to the positive terminal.  This is not recommended and would most likely cause more interference.

The ground wire should be connected to the negative terminal of the battery that the Humminbird unit is connected to!

Robert

[jseasor]

im really surprised this didn't work, it has in the past for many people.

it was worth a shot..sorry

[RGecy]

With the positive connection in the water you can create electrolosys on the motor and other metal parts.  Now, in fresh water, probably not a huge problem, but in salt or brackish water, you would eat up your motor, props, and anything metal.

Not good to put a positive connection in the water!

Robert

[nmanley]

With the positive connection in the water you can create electrolosys on the motor and other metal parts.  Now, in fresh water, probably not a huge problem, but in salt or brackish water, you would eat up your motor, props, and anything metal.

Not good to put a positive connection in the water!

Robert

Your right Robert, Not a problem in fresh water as it's not as conductive as salt water and the voltage is so small as well as we keep the boat moving a lot so it keeps the electrical field dissipated. 

HEY!!!  Maybe we can make the pulsing of hte trolling motor circuit create a electrical field in the water and stun some fish up to the surface!!  Just Kidding guys. 

I'm disconnecting the "extra gnd" wire from my setup and start looking into a better shielding device for the transducer from the motor. Might have some scrap tin laying around and really redneck engineer it into working. 

[Wayne P.]

Nmanley, I tried the redneck shielding deal with sheet copper and it had no effect on my interference. It did look good though.
After I removed my cable and transducer from the trolling motor, I just draped the middle of the cable across the motor housing and pushed the foot pedal button--yep still got interference on SI.

[RGecy]

Did you guys call Humminbird and ask about the new shielded transducers?

When we got the tour from Greg, we got to see them making the HDSI transducers with the new copper shielding inside.  Its supposed to help tremendously with the interference.  Not sure when they started shipping or if you already them, but I would check to make sure.

Robert

[nmanley]

Thanks for the update Wayne.

That last 798ci image I posted was with the new transducer. HB shipped out the interference kit to me last week. It came with the new larger xducer just like what came with my 898c. I'm using the Transducer Shield™ mount.

[QT]

All,
 I'm new to this conservation however, i had the dreaded interference and HB told me how to nip it in the bud!
I have a motor guide trolling motor with a 998c SI w/transducer mounted. I call HB and one of the techs told me to ground the negative lead(black wire of the power cord) to the trolling motor. I did this and the interference is gone. In order to make it a clean install, i grounded the wire to the trolling motor mount since they are electrically the same. The problem is gone and my 998c SI works like a champ. Let me know if this helps anyone.

Try it before you spend money on other options. 

[ZX225SK]

I had the same problem with my 898 and 997 I have fixed the problem. I ran a ground wire from my cranking battery through the hull up to the trolling motor and to the hose clamps that mount the transducer and bang all interference was gone. Such a easy fix. thanks to these forms. ZX225SK