Topic: 998cHD SI Noise

[Fender66]

It must be summertime when everyone is having issues because Cust. Serv. is unusually slow with their responses right now.  So....I'm coming to here for input on how to fix the noise problem that I get with ANY SI unit that I use on the front of my boat, mounted to my TM.  Here is what I've supplied to HB Cust. Serv. so far:

What model trolling motor do you have?     Motor Guide Pro Series

Does the trolling motor have the built in sonar?     no

Where is the transducer located for the 998c?     Bottom of the trolling motor mounted with a transducer saver bracket.  Top side of trolling motor has my Hydrowave.

Do you have the power supply for the unit and trolling motor connected in any way?  Power to the unit is supplied by the boat's starter motor battery....NOT the trolling motor batteries

Is there an onboard charger on the boat that connects the power supplies together?  YES....a brand new MINN KOTA MK 345 PC PRECISION DIGITAL CHARGER 3 BANK X 15A 

What software version is on your 998c?  Current software was updated when installed.  Don't know the software # off the top of my head.  It is network connected to my 798 unit.

Have you tried adjusting the noise filter in the unit?     Yes....does not help.  In fact, it degrades the image further.


Additional:


I did try to readjust the unit again while on the water this past weekend.  I noticed that the image seemed to get better when I let the unit "AUTO" find the depth rather than me setting a depth. (I get better pictures with my 798 when I choose my depth).  I also set everything back to factory default.  Improved slightly when trolling motor was not being used, but as soon as I'd use the trolling motor, it went bad again leaving noise lines across the screen.


I have also tried running an additional ground wire from the trolling motor to the battery. That actually made things worse.


They responded by telling me they were sending a PC11 power cable.  Isn't that the cable that comes with the unit?

I'm interested in any other thoughts anyone has.

Thanks,

Fender66

[Rickard]

Is there an onboard charger on the boat that connects the power supplies together? YES....a brand new MINN KOTA MK 345 PC PRECISION DIGITAL CHARGER 3 BANK X 15A

A common charger is actually a kind of connection between the power supplies. When I tried with a separate battery (a cheap MC-battery) for my sonar the interference problems vanished.
 
Rickard

[Humminbird_Greg]

Yes the Humminbird CRC folks are very busy this time of year and in particular the week after July 4th.  So give them a little extra time in responding back to you.

Yes the PC-11 should have been the same power cable that you received with your 998c HD Si unit.  This is the power cable with the lump in it.  I would call them back if you already have one of these installed.  Getting rid of or filtering out trolling motor noise interference is done step by step, so you may have to work with them and try several different things before finding the one that works best on your boat.

[ITGEEK]

This is a very common problem.
The transducer, which is designed to pick up
signals is attached to an electronic motor.

In some cases, you may not be able to fix this.
You may have to install your transducer on the transom.
I would make sure that the wires to the transducer
are kept away from the trolling motor wires.

If your sonar is wired to the starting battery of your
main motor, is the main motor off completely when you
see this interference?

Also, are the wires to the main motor battery and
trolling motor battery kept apart?

[Fender66]

Yes...the main motor is off completely when I see this. (I'm NEVER on the front deck when the big motor is running)  It is only seen when the TM is engaged.

Yes...the wires are run on separate sides of the boat to keep them away from any interfering signals from other wires.

Still....the down imaging pictures are still not as good as the ones I got from my 598 unit that was on the front deck and run exactly the same as the 998 unit that's giving me problems now.  The 598 unit almost gave me picture perfect views of the bottom compared to the 998 unit now.

Thanks for the replies....I'm persistent...(some may call it stubborn)...and I'm not giving up.

[ITGEEK]

The 998 may be more powerful and sensitive
than the 598.
I don't blame you for not giving up.
There is a checklist, and many options to try.
I would methodically go down the list,
retesting after each change.

It is possible that a newer software update may
help some.

Good luck.