Faulty raymarine depth sounder

[mackenzie]

Hi Folks

I just got a new boat, a 40ft spacesailer. In love with the old girl but sadly her electronics are just that.... old. One of the more important pieces of electronics that isn't currently working is the depth sounder.
It had a depth sounder fitted that was just displaying 0.0m. In a box of assorted junk the previous owner left me was another depth sounder of the same brand and make. I plugged it is and it gave a reading but the reading kept fluctuating from 7.7m all the way to 12m and displaying everything in between. I am just curious if it is the transducer or the head unit that is likely to be at fault.
I really don't want to have to replace the transducer if I can avoid it, especially if it isn't at fault, is there a way of testing the transducer that anyone knows of?
Is this a problem anyone else has had?

Mackenzie

[the_alpine]

It's usually the display.

Would help if you could name the equipment models

[boatbod]

Transducers do go bad over time. My professional recommendation is to get a new transducer, hang it over the side (in the water) and temporarily connect it to the display. If the depth works, you pull the boat and install the thing permanently, otherwise it's probably an issue with the display.

[nigelmercier]

Just in case ...

It has to be in the water!