I have a Minnkota Terrova hooked up to Humminbird 688, the 688 worked perfectly before hooking up to the Terrova.
The 688 now never locks on the bottom, this is the screen I get, all the time the depth is searching for the bottom, jumping all over the place.
I had the built in transducer removed and replaced, changed out the adapter cable twice, and have run a jumper wire from the battery
to the fishfinder as requested by the factory. I still get this picture. everything else works on fishfinder, by the way this was taken
in 20 feet of water. I have Diamond Sports Marine helping, and we have a call in to the factory.
Just wondered if any one else had like problem,...thank JIM

When I had a HB500 series, I called Cust Serv and they sent me a PC-11 power cord filter. Although the description does not list the 600 series it probably will work considering the 500 series isn't listed either. This is what cleared my interference with the Terrova. BTW, HB did not charge me.

I called CS, and was told that fishfinders with Down-Image wont work with Terrova.
any one wantta buy a 688,..?

You should have gotten the correct model of the 688 that works with a dual beam transducer. 688ci HD Combo.
Trolling motor built-in transducers are 2D only, they don't have an imaging crystal.

Thanks Wayne, the Fishfinders came before the Terrova, now I know the rest of the story.
What would be a good fit in the same price market as the 688..??

Just mount your transducer on the trolling motor. I don't use the built in transducer because i want fown and side imaging

If you want to use Down Imaging on the trolling motor, get the proper transducer for that purpose.

XTM 9 DI 25 T.

It is a trolling motor puck and has extra internal shielding for help with possible RFI from the trolling motor.
Bottom line--use the correct parts for the application.

thanks