I have a HDS7 and a HDS5 on my G3.Was not having any problem's with them until I loaded the new 4.0 software in them.Now I am getting 1/4 to1/2 inch line's on the sonar screen running in the direction from 7 oclock to 1 oclock.Lowrance told me that was one of the problem's with that update and to put the 3.5 back in both unit's.Did that and I still have the line's,so then they said I was getting some sort of electrical interference from my boat,so while they were on the phone I unhooked everything on the boat from the batteries and drifted and still line's.Lowrance said I was still getting electrical interference,now how could that be with everything being disconnected?Came home and checked all wire's for voltage and continuity to the hull and found no short's,and even if there was one it would blow a fuse or trip a circuit breaker.I'm wondering if going to 4.0 and then back to 3.5 if it erased all of the 4.0.Any suggestion's?

