Trolling plate and fish finder interference

[7 REM MAG]

Hey folks.

I have an 18' Jon boat, 90 horse Yamaha and put a trolling plate on the motor to get my trolling speed below 2.4 mph. This worked great for 3-4 yrs, however this spring i got my boat out of storage to prep for the season and found my finder wasn't working, and ended up replacing the power cable as connector was corroded.

Went fishing this past weekend, first time out since I replaced the power cable and when I put my trolling plate down there was so much interference that you couldn't make out anything on my finder screen. Couldn't see any fish, couldn't see bottom, etc. now it's a little odd because this wasn't an issue with the old power cable in previous seasons.

Wondering if anyone has run into this before or has any thoughts on the matter.

Thx

[EZM]

Might sound obvious, but first thing I'd check is to see if the position of the transducer is different somehow? maybe it got knocked somewhere and tipped back one click maybe????

Changing the power cable (assuming you are talking the power from battery (supply) to the head unit should have nothing to do with it (unless I'm missing something).

I'd also maybe check Hz settings? maybe that changed and cone width and/or frequency is better on another setting.

Keep us posted ..... this are the first two things I'd check anyway - hopefully it's that easy ......