trouble shooting loss of position.


It started intermittently upon startup. Sometimes I did not have my lat lon position and could not use waypoint navigation. shutting down the entire system (MFD and everything else networked) sometimes brought it back up. No longer does that work. I still have the correct time bing displayed. I updated software to 3.12. No change. How do I determine the problem? Is there a way of checking the gps 330B antenna? I have looked in Data Acquisition and in sky view. I do not see any satellites. Should they show if the antenna is working?
I would first check if the Problem is with the gps antenna or the wiring.

I assume that your atenna has a clear view to the sky?

Do you have any other unit using the gps Position, RD-33, autopilot,Navtex or Radio for example? If yes, same Problem there?

Do you have other nmea2K Units with may caus Trouble on the bus? One faulty cable or missing Terminator can cause Troubles with "funny" results
I only have the TZT14, a depthfinder and sirius weather. The gps goes directly into the network. Clear view with the antenna. No other connections. I just wondered if I should be able to see satellites in the sky view when go there. Nothing shows up when I check which made me wonder if they were supposed to be shown on the circular diagram. The first 330B antenna that I bought did not work at all. Furuno replaced it with this one under warranty. I guess there is no other possibility than the antenna.
Do you see the GP330B under your sensor list (MENU - INITIAL SETUP - Sensor list button)?
Do you see ANY NMEA 2000 items in your sensor list?
Sorry to say so but there is always another possibility ;)

One faulty gps Antenna might happen, but two of them in a row?

Of course you should see satellites in Sky View. And N2K is a Little bit more demanding than n0183.

Maybe your tzt has a defect or the n2k junction box. I think best practice is to narrow the Problem and first of all check every inch the wiring and also if power on the bus is ok. Perhaps you can get your Hands on another n2k unit to check if this gizmo showas Position. or Change the ports of the n2k junction box....