When I am using my downs can and I use my trolling motor it puts a black bar on my screen until I get off of the trolling motor. This is frustrating when tryin to sty over or look for brush piles on my downscan. Sorry new to the HDS system please help.

I found this fix on internet and it worked perfect for me. Connect a wire from the black feed wire to the sonar unit and clamp the other end to the troll motor shaft. I just tightened it into the shaft clamp on the mount. Eliminated all interference.

This can be a very difficult problem to isolate and fix BUT, it has been discussed many time here on the forum. Do a search and spend a few hours reading up on the issue.

How about a photo of your fix?

Do you have a LSS-2? if so, try 455khz

I put an internal ground in the TM and ground it to the boat. Works 99% of the time.

run a ground from the starting battery to one of the trolling battery ground minnkota used to supply a wire for just that , guess they don't do it any more ,I believe I have one in my parts box

The "add ground strap" suggestions (between cranking and trolling motor battery grounds) can and will damage an internal transducer (US-2) if present in a trolling motor. And it does not eliminate the actual source of the interference.

Best to eliminate interference or at least shield your sonar from it if you have US2.

Here's one method that won't damage Minnkota US2 transducers: http://www.amazon.com/AS225-125A-Ferrite...ds=ferrite+core

This is the same "fix" that Humminbird recommends/provides except a slightly larger size for transducer cables with larger connectors such as Lowrance.

You will need 2' or so of slack in your transducer cable. Disconnect the transducer cable from the unit and wind the cable through the ferrite core 8 - 10 times by passing the connector through the center of the core, then reconnect to your unit. Cable turns through the toroid should be somewhat evenly spaced and secured with plastic ties to keep them from becoming loose.

Nothing short of TM redesign can "eliminate" the source of the interference as suggested!

Worked for me!

C.

Really? Guess you haven't worked much on trolling motors and repaired bad brushes, loose connections, bad grounds, failing circuit boards.....

You are correct - I haven't done a lot of trolling motor repair, however it is a well known fact that modern TMs with the pulse speed control technology are the source of most TM/sonar interference these days. You can replace brushes, circuit boards, etc. all you want to but the pulse speed control system will still produce interference that impacts most sonar equipment!

C.

I just made a homemade spacer that I mounted between the head of the tm and the ducer and mine works fine.

Might mention that this fix corrected my interference between a Motorguide digital w/o internal transducer and a Humminbird dsi. Also noted that before installing the wire the interference cleared up on its own when motorguide was dialed up on full power rather than any variable setting.