ST50 wind instrument problem


Active member
16 May 2001
Winter St Ives, Cambs; summer Ionian
My ST50 wind instrument has started the season by only displaying wind direction, and not speed. Although I've had the bearings in the transducer replaced, I suspect the fault may lie in the instrument head.

Can anyone please tell me which of the 4 wires connecting them, red, yellow, green and blue, handle direction and which speed, and what sort of signals should I expect to see on the wires if everything is working ok?


Tony MS


20 Jun 2004
Essex, UK
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I have the very same problem with ST60. This may help you, found by search the forum, wire may be the same for your ST50 :

'If you have a junction box in line with the masthead cable (typically near the base of the mast) you can verify if the wind transducer is functioning properly. You will need a DC Voltmeter to perform this check

With the wind instrument turned on check between the following colors using the bare wire as your reference –vdc (ground)

Red Wire = 8+vdc (voltage supply from head unit to the transducer)
Blue Wire = 2-6vdc (wind direction from transducer)
Green Wire = 2-6vdc (wind direction from transducer)
Yellow Wire= 0-5vdc (wind speed from transducer. This signal will varying with changes in wind speed [the signal is a square wave whose frequency varies with the wind speed])

If the above signals are not present from the wind transducer then there may be break in the cable or the transducer has malfunctioned. The transducer must then be repaired or replaced. The wind transducer is not field serviceable and should be serviced by our factory repair or an authorized Raymarine distributor or dealer.”

The 2-6V for the wind direction vary according to the rotation of the vane. When the vane is rotated in one 180deg plane one of the wires will vary from 2-6V, in the next 180deg, the other wire's voltage will vary. If you get these variations then you can feel reasonably confident that the problem is not with the transducer or its cables and most likely in the instrument itself.'

Good luck !