Faulty Transducer?

[SteveGorst]

My boat came with a NASA Target depth unit. It has always been temperamental about giving me a depth. Sometimes it is flicking between 2 depths for instance 8m and 4m and a lot of the time it just reads 00.00m even when I come back into shallow water. Anything over 20m or so is out of range. But then my keel isn't that long so that is not too much of a concern Originally it was set in a tube full of oil so I set it into epoxy paste bonded to the hull to see if things would improve. It didn't. It is mounted in front of the keel but not so far forward that it comes out of the water or has air bubbles. I am wondering what to do next. I have read about using liquid slow setting epoxy instead and could try that to see if it works but could it just be a faulty transducer or would a faulty transducer just not work at all? Can they lose some of their power or something. I would have thought it would be binary, they either work or they don't. Or could it be a faulty head unit?

 

[VicS]

My boat came with a NASA Target depth unit. It has always been temperamental about giving me a depth. Sometimes it is flicking between 2 depths for instance 8m and 4m and a lot of the time it just reads 00.00m even when I come back into shallow water. Anything over 20m or so is out of range. But then my keel isn't that long so that is not too much of a concern Originally it was set in a tube full of oil so I set it into epoxy paste bonded to the hull to see if things would improve. It didn't. It is mounted in front of the keel but not so far forward that it comes out of the water or has air bubbles. I am wondering what to do next. I have read about using liquid slow setting epoxy instead and could try that to see if it works but could it just be a faulty transducer or would a faulty transducer just not work at all? Can they lose some of their power or something. I would have thought it would be binary, they either work or they don't. Or could it be a faulty head unit?

Any damage to the cable?.. Connection at the instrument end good?

Replacement transducers are available from Nasa

 

[SteveGorst]

Connection at the instrument end good?

I cant see any damage but the connection would indeed be worth checking and I haven't. It may have oxidised up a bit so I'll give it a spray with the magic spray and see if it improves. Funnily enough I had to do that with the plotter this weekend....

 

[Daydream believer]

Do you have any sign of condensation in the display unit? It may not be the transducer.
If you can remove the cable easily to get the transducer free, just dangle it over the side when in a marina or on a mooring & see if it works. That will test the transducer.

 

[SteveGorst]

Yes you were right is was the display unit. I replaced it at the weekend and left the transducer in place. All working fine now. Another issue I noticed a couple of weeks ago was interference on Channel 80 when standing close to the instruments. That has also been fixed by replacing the display unit.