ITC-5 i70s Wind Depth Sensors

[olesenrl]

I have been having erratic operation of the wind and depth sensors for two years now . I have replaced everything. Sometimes the wind speed and/or direction drops out. Sometimes the depth drops out. I have two i70s instruments, the GPS location form the 150 shows on one but not the other display. I have a new AIS 650 installed, the AIS shows on the same good i70s but on the other it says the AIS is off. The i70s's are connected to a SeatalkNG to Seattle converter. The Seattle spur is then connected to the 6001 autopilot. I noticed on the ITC-5 they are flashing led green lights, what does this mean? The backbone is installed correctly. I replaced the ITC-5 with another brand new one, and the problems with the instruments got worse. Except for the one Seattle spur to the autopilot everything is SeattleNG now. As both the wind and depth are intermittent it has been almost impossible to debug this. Everything on the SeatalkNG backbone is now new except the autopilot. I have removed the autopilot from the backbone but the wind and depth are still intermittent. What steps should I take? Could this be an issue with a noisy or bad ground?