Odd i70 malfunction?

[Steve - Raymarine - Moderator]

It does point toward a power issue on the Seatalk NG backbone, due to the fact that the issue you are explaining is a loss of data at the i70's which are repeating the data they are getting from the Seatalk NG backbone. When the i70 displays are displaying the issue, you can check power on the backbone by pulling the Seatalk NG spur cable from the back of the display and with the notch on the connector at 12 o'clock, measure with a voltage meter the two holes to the left of the notch, first 12VDC+ and the second from the notch VDC-. What are you getting for voltage at the time of the issue?