ST 50 Mast Head unit repairs and part No's

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Mal113

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ST 50 Mast Head unit repairs and part No\'s

I recently, had a problem were my ST50 Wind mast Head unit was not giving an output to the display for wind speed. Having removed the unit I found the bearing supporting the rotor had collapsed and hence allowed the indicator to rotated but not on a true axis and hence there was no output signal. A little investigation found that the bearing and the Digital Position sensor (Honeywell SS 411-A, the bit that measures the 4 magnets on the rotor) could be purchase from Radio spares at http://uk.rs-online.com/web/ the RS part numbers for those interested are: -

Honeywell SS 411-A = 181-1463
Rotor bearing = 612-5739

The unit is now working as new all for under Ten quid.
 
Re: ST 50 Mast Head unit repairs and part No\'s

Thanks thats really useful information, there must be loads of people who have bought new wind instruments when a quick fix like this would have done the trick.
 
Just come across this thread - very useful as now the mast is down for the season I've got my ST50 masthead unit in my hands. The electronics work ok but I think the bearings are going as it has stopped turning intermittently all season.

The local shop has said no spares anymore and suggested WD40, but I'm very interested in replacing the bearings. Having prised the transducer out of the alloy cylinder - can anyone advise what to do next ? - its very small ....
 
I have the same problem with my NKE masthead unit, (although the gale on Saturday got it spinning again). If I remove the transducer how do you find where the bearings are made?
 
Don't use WD 40

I have the same unit, and last year I removed it to sort out the problems that I'd been experiencing. After some months of no wind speed or direction I gave it a liberal application of WD40, with no effect. I had read simliar threads, so I tried to disassemble the direction/speed unit, but due to my general cack-handedness I failed completely. Fortunately. I didn't completely b*gger it up.

I sent the unit off to Tinley Elecronics (http://www.tinleyelectronics.com/service.htm) to identify the problem and repair it. They berated me for using WD40 (damages the pcb's) and replaced the bearings. It certainly wasn't cheap, but it was quick and efficient.

Unfortunately, after the return of the head unit the wind speed still didn't work. I have to admit, much to my shame, that I didn't actually need to send the unit off in the first place. I had an open circuit on one of the cable cores up the mast. After replacing the cable with an equivalent (NOT the Raymarine cable at £xxxxxx/m), it worked perfectly.

Well, it worked all season until last weekend. The wind speed is now only working in breezes above 10 knots, so I reckon that some silicon lubricant will be necessary before next season. I only need to persuade my wife to go up the mast now. Wish me luck.
 
Tinley offer another option if repair of the head unit is not feasible. They will supply masthead units compatible with a range of manufacturers, don't know prices but here is the website: www.stowemarine.com.

Mine's going for an estimate so fingers crossed
 
Thanks for this Information. I could repair the ST50 Wind Mast unit. About the Position sensor is very importent that the Type is Honeywell SS411-A without any following letters. Honeywell has different types of SS411-A sensor. The type with a following letter has an other sensitivity and doesn't work (ex. SS411-A1F doesn't work)
 
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