I have an issue with my Nasa Speed Log. It powers up ok but when I spin the propeller no speed is recorded. I phoned Nasa and they said that the cable may need replacing?
What checks can I do to trouble shoot this?
Nasa logs are common. Try finding a boat with a similar set up and plug yours into that. That will test the unit. If it works then that points to the transducer/cable. Often the connection and terminals can get corroded, so a thorough clean may be all thats required.