Our Ray marine st 60 depth sounder quit working this week This was 3 year old replacement for OEM st 50.. Worked well. then displayed last depth reading 80 feet. Than now no display of depth just 3 horizontal dashes. Display of alarm sets are present and fine. Can display brightness setting . I removed Instr. from console and checked for loose transducer wire. seemed ok. trying to decern if problem is display or transducer. Any insight would be appreciated.