Wdeertz
Senior Member
I have a simrad autopilot depicted as the following simnet network. It’s been working fine for the past 4 years since I’ve owned the boat. Recently while underway the autopilot went blank (no heading shown) and stopped working. While looking under the service menu I noticed many nmea transmission errors. I disconnected the backbone cable going to the flybridge unit and placed the terminator here. The AP28 headunit worked perfectly with no nmea transmission errors. I removed the flybridge AP24 headunit and connected in place of the AP28 at the lower helm and the autopilot worked perfectly so I think I can rule out the AP24 unit is bad. I then connected the AP24 unit at the lower helm in place of the 6m backbone cable going to the flybridge and put the terminator in the 2nd connection on the AP24. With both headunits on the autopilot seems to be working fine with no nmea network transmission errors. As such I’m surmising the 6m cable going to the flybridge has gone bad. Any ideas how a nmea cable fully enclosed in a wire chase could go bad? Possibly chafing somewhere along the cable?
Is there an easy way to test that cable before I go to the effort of replacing? I was thinking of jumping the connectors with a wire to test continuity and resistance, what sort of resistance should it read? Thanks
Is there an easy way to test that cable before I go to the effort of replacing? I was thinking of jumping the connectors with a wire to test continuity and resistance, what sort of resistance should it read? Thanks