ST 60 tridata speed not working

[2383]

My ST 60 tridata speed was working fine at the end of last season. It is not now. The paddle wheels are clean, spin freely and are all intact. When the wheel is manually spun there is no speed on the readout. Do I need to replace the paddle wheels?

 

[john_morris_uk]

Did you remove the instrument head or change any of the wiring during the winter? The diagnosis is 'lack of pulses' from the paddle wheel. It could be the paddle wheel, the wire between the paddle wheel and the instrument head, or the connections on the back of the head or (unlikely) the head itself.

It might be a premature (and expensive) to start changing the wheel before you have thoroughly checked for wiring problems.

(PS It has been known for the paddle wheel to lose the magnets out of the impellor, but I haven't heard of that happening on a Raymarine instrument.)

 

[2383]

No obvious loose wiring. Is there any way of testing the wiring itself though? (Just to be sure)

 

[fireball]

First thing I do is unplug the cables and replug them back in - could just be a dirty connection....

If that fails an easy test would be removing your head unit and connect it to someone elses sender unit ..
or
Borrow someone elses head and connect it to your sender ...

that way you identify where the problem is.

Raymarine support in Portsmouth were very helpful when our ST50 tridata failed....

 

[2383]

Thanks, I'll try that

 

[owen]

it might be worth checking you have put the sender unit in the correct way.--- the sender unit will slot in easily 2 ways paddle wheel cups facing forward and also backwards

 

[Gin]

Me too- odd isn't it?

However, a similar thing occurred briefly last season and a little gentle wiggling of the 3mm spade end terminals on the back of the instrument did the trick.

Hope you are similarly lucky

 

[steve_cronin]

Is something going on?

Mine wasn't working all of last season having been put away in 2004 in full working order. on both winters the A/F was contracted out. However, I have a chart table ST40 repeater which was new last winter so I'm going to switch that to master & substitute it for the original.

Steve Cronin

 

[fastjedi]

For the second half of last season the blank was fitted in the belief that our ST50 sensor was knackered. On investigation over the winter I found a suspect connection ... but was unable to test as the batteries were at home. The batteries went down last week and the boat was launched. I tried spinning the paddle and it works /forums/images/graemlins/smile.gif trouble is I have applied just about as much force as I dare to remove the blank .... but it's well and truely stuck .... not a problem I have faced before .... and I don't beleive I antifouled over it either /forums/images/graemlins/confused.gif so it looks like I am going to have to dry out somewhere so we can push and pull at it.

 

[hightech]

Unscrew the display and unplug the transducer wires. Then with a paperclip or a short bit of wire tap (short) between the red and green connections on the back of the unit (with it switched on of course!) the speed you tap should show a speed on the display. This will prove (or not) the display is OK (or not).

If it works then the trnsducer needs replacing.

 

[2383]

Thanks for all the suggestions.
It turned out that the impellor had lost some of its magnesism (some attraction to my screwdriver). I replaced it (£25) Definetely more magnetic attraction to the screwdriver. System works fine now.
Thanks again.