depth sounder replacement

[ErikKiekens]

hello folks my depth sounder doesn't work anymore. The number goes crazy and keeps flashing, which according to the manual means "the return signal is not received, probably due to air bubbles". I also noticed that the sound is irregular. I can hear this when listening to Radio 4 on LW. So it is safe to conclude that the sounder is not properly working?
The sounder is an AIRMAR 20-386-02 and looks as if it is extractable so I could replace it while in the water. Can that be? I am a bit shaky about that although it's what I usually do with the log impeller.
It is difficult to find AIRMAR distributors on the internet; can I use any other model as replacement?
looking forward to your replies, as usual!
Erik

 

[Pye_End]

Presumably this is not a through hull transducer? If is is all inboard then in may well be worth making sure the contact inboard - eg. oil bath. You may even be able to take the transducer out and hacg it over the side to check it further. If it is a through hull transducer then they are susceptable to fouling, and a good clean may be what it needs.

Checking the connections is well worth while. Mine was not working properly (flashing) but turned out to be a poor power connection - it pinged as you describe, but not enough welly to get a good return.

 

[VicMallows]

I agree that if the transducer is in an oil bath, lack of (or aeration of) oil is the most likely cause. Otherwise also check the electrical connection from transducer to instrument. Could be intermittently short or open. Many seem to use 'belling-lee' TV antenna plugs which are notoriously unreliable.

 

[David2452]

hello folks my depth sounder doesn't work anymore. The number goes crazy and keeps flashing, which according to the manual means "the return signal is not received, probably due to air bubbles". I also noticed that the sound is irregular. I can hear this when listening to Radio 4 on LW. So it is safe to conclude that the sounder is not properly working?
The sounder is an AIRMAR 20-386-02 and looks as if it is extractable so I could replace it while in the water. Can that be? I am a bit shaky about that although it's what I usually do with the log impeller.
It is difficult to find AIRMAR distributors on the internet; can I use any other model as replacement?
looking forward to your replies, as usual!
Erik

That model was used with Raymarine ST series, Garmin, Nexus etc so one of their dealers will have a replacement I imagine, best match from rhe existing instrument supplier as some of the internal cabling can vary and plugs always do. It is through hull and replacable, a bit scary but there should be a plug aboard somewhere aboard, if not the new one should have one in the kit, the insert should be available without the through hull housing.

 

[ErikKiekens]

Thanks guys; I will have a look at the connection, if that doesn't solve the problem I will extract the sounder (the plug is the same as for the log and is lying next to it) and see if it needs to be cleaned. We have probably anti-fouled it. If that is a problem I don't understand why. My main hope is for the connection, because fouling would not explain why the sound is irregular.
If nothing helps I will replace the sounder. Thanks!!!

 

[richlear]

if the ping is irregular I would suspect the transmitter stage rather than the transducer. Fouling would certainly reduce the source level and cause other issues such as increased sidelobes but would not cause an irregular ping. I would start by examining the cable for damage then put a scope on the output of the tx (watch out for high voltage, these things can put out quite a punch) and monitor the transmission.

is it a dual frequency unit? is the behaviour the same on both frequencies?

Rich