DFF 3d torch beam

[stratboogie]

So, last week when I was out I started getting the "torch beam". After looking no here it seems to be a grounding issue. I took down the box and looked at the wiring for the transducer (I did not do the install of my 3d system). Everything looks right except the bare wire is connected into the same connector as the black wire. On the diagram it has common. Is this correct? Also, the installer did not install the clamp with the shielding. Anyone know what size screw those clamp holes are? I will have to make a clamp. Also, the earth ground is not connected. Do I need to connect that to my negative motor battery?

Thanks in advance

 

[Johnny Electron]

Everything looks right except the bare wire is connected into the same connector as the black wire.

The bare wire should not be connected to the same place as the DC neg wiring. The DFF3D should have most of the bare shields pulled back and placed under the metal hold down with the ground screen upon entering the unit. The unit itself should be grounded to a bonded system via the ground lug on the outside of the sounder.

Do I need to connect that to my negative motor battery?

What motor are you referring? Autopilot pump motor? Do you have a wiring diagram or photos of how things are wired on the boat? If you paid someone to conduct the install, you might want to contact them about the problem to see if they will come and resolve it.