Replacement Raymarine Speed/temp transducer

[sgreenway]

I was wondering whether anyone can assist.

I have a Raymarine ST60 speed/log/temp display connected to a through hull transducer.

I am getting 0 knots when sailing or motoring, and I am pretty sure I am doing more than that!!!! And according to the display the temperature in the English channel in July was 58 Degrees C.

Am I fairly sure that either the transducer or the cable is damaged, and so I need to replace it. I think the original was the M78172, which is obsolete.

Any suggestions?

 

[earlybird]

I was wondering whether anyone can assist.

I have a Raymarine ST60 speed/log/temp display connected to a through hull transducer.

I am getting 0 knots when sailing or motoring, and I am pretty sure I am doing more than that!!!! And according to the display the temperature in the English channel in July was 58 Degrees C.

Am I fairly sure that either the transducer or the cable is damaged, and so I need to replace it. I think the original was the M78172, which is obsolete.

Any suggestions?

I'm fairly sure that the current model transducer, supplied with the ST60+, will do the job, don't know it's part number though.
Before spending money however, it might be worth trying the following. Remove the temp.sender wires, brown and white, from the back of the instrument and substitute a resistor, ~10kohms, but not critical. You will need two 3mm connectors. See if the speed display then works. The reason for doing this is that the instrument is dependent on seeing the thermistor, which can and does fail. If this happens, the instrument thinks it's a slave and doesn't respond to the transducer speed signal. I've experienced this with my Tridata. Can't remember if the display showed 000's or ---'s though.
You've presumably done 6he obvious check that the paddle-wheel is free to rotate.

 

[Twister_Ken]

Raymarine (and other) transducers are made by Airmar. A visit to their extensive www will show you what is available. It won't be a problem to find a current (geddit?) product compatible with ST60s.

 

[sgreenway]

I'm fairly sure that the current model transducer, supplied with the ST60+, will do the job, don't know it's part number though.
Before spending money however, it might be worth trying the following. Remove the temp.sender wires, brown and white, from the back of the instrument and substitute a resistor, ~10kohms, but not critical. You will need two 3mm connectors. See if the speed display then works. The reason for doing this is that the instrument is dependent on seeing the thermistor, which can and does fail. If this happens, the instrument thinks it's a slave and doesn't respond to the transducer speed signal. I've experienced this with my Tridata. Can't remember if the display showed 000's or ---'s though.
You've presumably done 6he obvious check that the paddle-wheel is free to rotate.

I've checked that the paddle wheel rotates, it does. No speed on the display though :-(

 

[RMA]

I have a brand new speed/temp paddle wheel transducer which I don't need. It's still unwrapped. The model is ST800. It is for the ST60+ although I believe it will work with the ST60. PM me if you are interested in buying it.

I thought mine had packed up but eventually I traced the problem to a bad connection on the back of the head. In my experience most ST60 problems are bad connections.

 

[sgreenway]

I have a brand new speed/temp paddle wheel transducer which I don't need. It's still unwrapped. The model is ST800. It is for the ST60+ although I believe it will work with the ST60. PM me if you are interested in buying it.

I thought mine had packed up but eventually I traced the problem to a bad connection on the back of the head. In my experience most ST60 problems are bad connections.

I am a new "boater/yachtie" whatever the term is. How would i go about checking the connections, primarily for speed/log. not too bothered about temperature.

 

[WALLY]

The standard ST60+ speed transducer is part number E26031

 

[misterg]

...How would i go about checking the connections, primarily for speed/log. not too bothered about temperature.

You might not be bothered about temperature, but the instrument is: As earlybird says, if it doesn't see what it considers to be a 'sensible' temperature, it switches to being a repeater and ignores the transducer.

You need to get it to read a normal temperature (by finding & fixing a poor connection if that is what it is, or by 'frigging' the instrument with a resistor across the temperature sensor inputs) before you will know whether there is a fault with the speed transducer or not.

I would start checking the connections be going over every connection between the log and the instrument looking for loose wires, water corrosion, etc.

Don't ignore the complication of the temperature input serving two purposes.

0.02p

Andy

 

[RMA]

You need to get to the back of the instrument head. It’s usually held in place by two knurled nuts. Disconnect the three wires which on mine were fitted with fairly small spade connectors – the wires are colour coded so you shouldn’t mix them up when you put them back. Tug each connector to make sure it is fixed securely to the wire (that was where my problem was) and replace them if there is any doubt. Best to use a ratchet crimping tool if you can get hold of one. Then make sure they are fitted firmly to the terminal.

 

[sgreenway]

I actually made a slight c**kup. I was on the boat at the wekend and double checked it all.

I have an ST60+ tridata display (speed/depth/log) and so i guess that the ST60+ speed transducer would be OK!!!!

At the back of the display there are 5 small spade connectors all in the section for Speed.

I have checked each of these connectors and all seem good. I am therefore assuming that the transducer or cable is broken.

The speed transducer itself can be removed from the through hull mounting (and replaced by a blank).

 

[earlybird]

[QUOTE

At the back of the display there are 5 small spade connectors all in the section for Speed.

I have checked each of these connectors and all seem good. I am therefore assuming that the transducer or cable is broken.
. QUOTE]
Do you have a reason to suspect damage to the cable? There will probably be some external sign. If so, you could cut and rejoin or, if you're very lucky, find enough surplus length to discard the damaged section, but that would apply only near the instrument head.
Failing that, you have two possible courses of action:-
1) Buy a new transducer. AFAIK, this will relieve your wallet of over £100 and could provide a goodly period of frustration re-running the cable. ( Use the old to thread the new one). This will most probably cure the problem, although there remains the slight chance that the display head itself is duff.
2) Do as suggested in the earlier posts and fit a resistor of about 10 kohm across the brown and white terminals of the instrument.This will cost a few pence and will take moments to fit if you can solder. It is not a guaranteed cure but since you have temperature reading in error, it seems quite likely to be. A 10k resistor will give a fixed reading of ~25 deg.
PS Raymarine paddlewheel transducers are interchangable between ST50, 60 and 60+, including tri-datas

 

[sgreenway]

Just a message to say thanks for all the information and assistance.

I placed the 10kohm resister across the relevant points and got SHMBO to rotate the paddlewheel. Guess what - it worked!!!! well she could only rotate it at a peal of 0.5kts.

That is the fastest I have seen my display since I got her!! The boat that is!!!