No data - ST30 Speed instument

Jun 4, 2004
834
Hunter 340 Forked River, NJ
So I have these old Raymarine ST30 depth and speed instruments linked to an ST60 wind meter on my 2000 H340. The ST30 speed stopped working this summer. The display seems fine and I can toggle through the display functions but I get a zero for the boat speed. I pulled the transducer and found no damage and the paddle wheel spins freely but gives no reading on the display. I removed, cleaned and replaced the wires on the back of the display unit but still get no data. I can’t seem to find any source for a replacement transducer for the ST30. Does anyone have any information and/or advice on further troubleshooting or replacing the instrument with a newer model. I would like a replacement that will interface and work with my existing ST30 depth and ST60 wind. The instrument cluster is connected with the Raymarine SeaTalk cable. I have a suspicion that any new transducer will require the remove of the old thru hull and possible drilling of a large hole or worst yet, needing a smaller hole. I have call into Raymarine technical support and I am waiting for their input.
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
All the speed tranducers I've seen use a paddle wheel with a magnet in one of the baldes. As the magnet passes through the upper part of the transducer it passes a coil of wire and causes a voltage pulse. Each pulse is read by the control head and it converts it into speed and distance. So I'm thinking that the first thing to check is the transducer output. Disconnect the transducer at the control head and set your multimeter to AC volts (0-5 volts). Then have a helper spin the paddle wheel. A can of compressed air is handy for this. The keyboard cleaning stuff. If that fails then I'm pretty sure all you need is any Raymarine speed transducer that will fit in the existing hole. If it passes then your control head may have demon infestation and be in need of a good prayer session. Pull it apart and see if the transducer wires are corroded or broken etc.
Good luck.
 
Jun 4, 2004
834
Hunter 340 Forked River, NJ
Thanks Bill, part of my problem is finding a replacement transducer. I can't sem to find the dimensions or specs for newer transducers.