szigi ... my apologies, i missed your reply but you were absolutely correct in your assessment.
So .... we've done a lot of playing around with no results until yesterday. First up we put a voltmeter across all connections and they were all good bar one which had signal but it didn't waver, which it should as the wind moves around. This was the same at instrument and at deck connector. Ergo, the problem was up top so we sent the Wombet up the mast to dismount the transducer.
Testing of transducer showed that a thing called a "Hall Effect Sensor" was kaput so its either replace the whole assembly and/or replace the HESs which is doable if you are dabbish of hand with a soldering iron. New HESs are now coming from the US for the repair but I'm thinking to get a replacement full assembly as well.
So .... the problem becomes one of which transducer ? The original
or the newer version ..
Anyone have any thoughts ?
The newer btw is twice the price of the old.