Autopilot not working, no GPS position - general suspects?

[Krumelur]

When I moved my boat back from the crane to its mooring I noticed that autopilot would not work.

* The plotter doesn't show a GPS position (see image). If I enter the GPS settings of the plotter, it cannot get a fix. In fact, it is not showing anything, just as if there was no GPS input at all.
* The VHF radio however did show a position. But only sporadically. Now it's not showing one at all.
* The cockpit instruments show "No GPS fix" and "No pilot".

Now, I'm looking for a hint where to start. I haven't even found the GPS antenna, which would be my first guess.
The mast was taken off and put back on and they had to disconnect a bunch of cables but I'm not convinced working at the mast would affect the GPS.

What should I check? Where could the GPS antenna be? Is it common to keep it close to the plotter (which is inside) and shove it up into the hull behind the panel? I looked but was unable to get my head in deep enough.


This is on a Bavaria 40 from 2010, by the way.

[tiger79]

The GPS antenna is inside the plotter.

[Yngmar]

Looks like a N2k network. Since it occurred after a mast job, it's almost certainly a break in the N2k bus, which would show exactly those symptoms. Check for loose/unconnected T-pieces.

[Krumelur]

If the gps antenna is built-in, and GPS is no longer working, that would mean the plotter is broken, right? It’s an A75 Wifi.

Does the autopilot get the gps position from the plotter?

[Krumelur]

More updates. The A75 has a setting to enable the internal GPS. This was OFF. I haven't turned it off, so I assume it was off off before.
If I switch it on, I'm getting the GPS position displayed on the plotter. Some progress. Still, I'm assuming an external GPS antenna was connected and still is, but does not work as expected.

However, going into the plotter's setup and making it search for GPS sources, I'm getting a popup about some devices blocking the "orchestration" (see photo). The popup says, this was not an error - but what else?

Furthermore, if I try to setup the P70 in the cockpit, it's crashing.  It's always showing "no pilot". If I enter the setup and make it search for sources it will reboot.
The i70 will show depth information sporadically. The error about "No GPS fix" is gone, as long as the internal GPS of the plotter is enabled. Trying to configure a different GPS source on. the i70 tells me that it is "impossible". At least, it's not crashing like the p70.

I'm waiting for the electrician who reconnected the wiring. Hoping he will find the issue.

[Krumelur]

I found the GPS antenna. It's hidden behind the locker in the nav area. The GPS antenna is connected to a SeaTalk-5 connector. If I disconnect it there, the screen that showed 2 devices preventing orchestration will then only show one. If I disconnect another one (black-blue, the cockpit instruments I suppose), the auto detection of devices will succeed. It will then find the internal GPS as only source (obviously, as the external one is disconnected).
If I try to find any other sources for wind, depth, speed they will come back empty. Which brings us back to the mast work, because those sensors are "behind" the mast.

[IslandAlchemy]

Seatalk NG issue. Check all the cables and connectors.

[SYJetzt]

I suspect your seatalk NG network has an extension to the mast to connect your wind sensors....
The Seatalk NG backbone needs end terminators (2 pcs., one at each end of the cable).
If this terminators are missing, you will see problems like you mentioned....
For wind sensors some raymarine instruments have the termination included in the sensor.
I assume, the seatalk NG backbone connection to your wind sensor has been disconnected, causing this erratic issues, maybe on all systems connected to the N2k backbone (and not only from the mast instruments..).
Check  the mast connections with diligence...

[Krumelur]

Thanks for all the input. Learned something new again: SeaTalk and SeaTalkNg :-)
In the end, I think I found the issue. Checking all connectors thoroughly was key to success.
The connector of the p70 is not in best shape. Slightly moving it would power down the device. After I disconnected it, the external GPS antenna worked again and depth, wind, speed are reported correctly.
I gave the connector a bit of WD40 and let it soak in as there was some visible corrosion going on with the pins.
Now it's reconnected and things are working. I think I'll replace the p70 with a newer version. The keypad on this one is done anyway.

Awesome forum!