ST60 Speed impeller

[MarkTheBike]

Dear all

My speedo isn't registering any more. I've spun the impeller by hand but nothing. How can I test whether it's the impeller that's failed or the unit? The speedo has been iffy from time to time in the past but would then start working again but now is solidly not registering anything. I've got a multimeter but nothing more sophisticated. Any info welcome....

Cheers

[tiger79]

See http://raymarine.co.uk/knowledgebase/index.cfm?view=3791

[MarkTheBike]

Brilliant, Tiger, thanks - just what I was looking for. I did a search and nothing came up for Raymarine but it looks quite a useful forum so now in my favourites list. Thanks again.

Cheers

[stardust]

Have just had a newT60 speed transducer fitted(by a technician ),he joined the cable behind a locker .took 30 mins tops and about 100 euros

[MarkTheBike]

Thanks for the info, Stardust. I've been delving into the electrics at the back of the pedestal panel (ST60: Tridata/Multi/Wind & 4000+AP). I jiggled a few connections, blew on the log impeller and bingo! it worked. Shut down, went home, came back. Nada! I've now taken all connections off, cleaned them and replaced them. Still nothing, not even a glimmer so I'm none the wiser. If it was a loose connection, why hasn't cleaning them all up sorted it? And if it was the impeller, how did it suddenly work after wiggling wires 7m away? I put the voltmeter across the +12V feed to see if there's not enough oomph but it registered a steady 12.2V so it's not that. My voltmeter showed an open circuit all the time when attached to the Green / Screen (ref: Tiger's link above) but that may be because the meter battery hasn't got enough power for the cable length so I'll rig a 12V test light next time I'm down...

Cheers

[geoff]

If the temp indication is not working it is the impellor unit. Geoff

[stardust]

The Technician took the leads off the back of the instrument and tapped one of them against the terminal ,the speed read and he said it was either the cable or the speed impellor. the wire  in the forward of the hull where salt water accumulated after inserting the impellor was corroded and very brittle.
Incidental he also fixed the VHF which was not receiving..Took it apart and changed a filter for 8 euros plus 30euros for man hours.Very impressive in this throwaway age

[MarkTheBike]

If the temp indication is not working it is the impellor unit. Geoff

The temp is working correctly. It was showing 21.6C this afternoon. Blimey, time for a swim, I thought. Then the lightbulb goes on - the impeller unit is inside the boat whilst I'm testing it so it's reading air temp. Doh!

The Technician took the leads off the back of the instrument and tapped one of them against the terminal ,the speed read and he said it was either the cable or the speed impellor. the wire  in the forward of the hull where salt water accumulated after inserting the impellor was corroded and very brittle.

Do you know if it was the GREEN wire that he tapped? I guess it probably was as I assume that's the signal feed from the impeller (according to the testing instructions in Tiger's link above). More jiggling wires today has revealed nothing new but I'm back there tomorrow so I'll give the tap test a go.

Cheers all....