Hello from the Mediterranean,
Autohelm electronic compass.
Following a spring clean up in the forward cabin, I removed the floor panel under the twin berth and the 12 v bulkhead mounted compass  under it. After everything was fitted back into place, the reading of the electronic compass was wrong by 180 approximately or less. I first thought it was my mistake so I repositioned the compass accordingly in order to cancel the wrong reading but it didn't change anything to the displayed reading from the cockpit Autohelm 4000 central station.
 So, after all, I decided that the problem had nothing to do with me but happened by accident. Has anyone had a similar problem?
 The other problem I am facing is with the Garmin GPS map 292. I have no more reading after the antennae was blanketed by the installation of two solar panels.  Therefore no more positioning can be reported to the B&G remote  repetitor and, consequently, to the interfaced VHF. There is no alternative to reposition it. I thought the central station had a backup antennae but that does not seem to be the case. Can anybody confirm this? 
Thanks and fair sailing.