Lines across my SI.

Each time I hit bump the TM , my screen on humminbird starts a little lighter line and when I let up on TM it goes darker. It did not do this when used on my other boat. I assume its because Transducer cable did not run beside power cords for TM. Is this correct assumption?

While it does not bother me alot, I would like to have solid coloring across screen ( easiers to tell drops) and I would like to know what it is and will it "Hurt" the screen or something:dono

Charlie, have you looked at this thread? http://www.crappie.com/crappie/fishi...erference.html

Sorry.. I posted quickly wondering if it was this site I had seen good info on this, kinda knew I was:deadhorse.. Thank you BB ( to my aid again!)