The exact same thing happened to my 997si a couple months ago.I have my transducer on my jackplate on a transducer shield bracket also.I have 2 boats,that I use the 997/957 and just switch back and forth.i purchased extra gimbals,transducers and gps antennas so I can just unplug and switch boats.one boat has y cable with two transducers and the other has single transducer.I get a dark si/di screen now,and this unit has been fantastic up until this year.i borrowed a buddys 997-and it works perfectly on both of my boats.I hate to warn you,but when you call humminbird customer service-they will tell you the same thing they told me “your unit is too old,and we dont service them” and “we dont even have parts for those 9 series units” blah blah blah.Helix/Onix cannot be linked to “old” units either.
