Raymarine

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Graham_Wright

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My rudder position sensor has developed a fault giving erratic readings.

Removing the cover plate, I found a simple potentiometer as expected with an intermittent wiper contact.

Curious about the cost, I scanned ebay and found prices up to £311!

I like Raymarine but, for such a simple device, that is outrageous.

Hopefully I can replace the pot without too much difficulty.
 
I don't know how old or what model of course computer you have but some of the lower end course computers don't need a rudder position sensor.
Hence if your course computer is really old and you are considering buying a new sensor it may be worth skipping the sensor and putting the money towards a new course computer.
 
Graham_Wright said:
Curious about the cost, I scanned ebay and found prices up to £311!

I like Raymarine but, for such a simple device, that is outrageous.
Click to expand...

What's outrageous is that you should criticise Raymarine for this! Everyone knows that eBay prices are often ridiculous. The rotary rudder sensor is widely available for around £150.
 
Graham_Wright said:
My rudder position sensor has developed a fault giving erratic readings.

Removing the cover plate, I found a simple potentiometer as expected with an intermittent wiper contact.

Curious about the cost, I scanned ebay and found prices up to £311!

I like Raymarine but, for such a simple device, that is outrageous.

Hopefully I can replace the pot without too much difficulty.
Click to expand...

Post a picture - the pot may be a standard part you could replace and someone here might recognise it.
 
Talulah said:
I don't know how old or what model of course computer you have but some of the lower end course computers don't need a rudder position sensor.
Hence if your course computer is really old and you are considering buying a new sensor it may be worth skipping the sensor and putting the money towards a new course computer.
Click to expand...
It's worth adding the rudder ref unit to the new computers too. A marked improvement when fitted.
 
JohnGC said:
Post a picture - the pot may be a standard part you could replace and someone here might recognise it.
Click to expand...

The unit dismantled quite easily and the pot declares itself to be Vishay Spectrol type 357-4158-502. My crummy dvm measures 4.9k ohms. As there is a 5v potential across the ends, I guess that the resistance is not critical within 20 or so percent.

My searches have failed to find a source so far. The shaft is 22 mm long and ~6 mm diameter. Connections are on the base.
The Vishay website shows similar models but could not recognise the reference number. I have contacted them.

The appearance is as here;- www.ebay.co.uk/itm/like/12110411838...f11=ICEP3.0.0&ff12=67&ff13=80&ff14=101&ff19=0
 
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I paid £100 new for mine from eBay. All rudder sensors are surprisingly expensive but there are only really two (plus niche) players in the game so what can we expect?
 
Graham_Wright said:
The unit dismantled quite easily and the pot declares itself to be Vishay Spectrol type 357-4158-502. My crummy dvm measures 4.9k ohms. As there is a 5v potential across the ends, I guess that the resistance is not critical within 20 or so percent.

My searches have failed to find a source so far. The shaft is 22 mm long and ~6 mm diameter. Connections are on the base.
The Vishay website shows similar models but could not recognise the reference number.
Click to expand...

It's a model 357 pot - the Vishay data sheet should enable you to source a replacement as it explains the current part number system - http://www.vishay.com/docs/57059/357.pdf
 
Graham_Wright said:
The unit dismantled quite easily and the pot declares itself to be Vishay Spectrol type 357-4158-502. My crummy dvm measures 4.9k ohms. As there is a 5v potential across the ends, I guess that the resistance is not critical within 20 or so percent.

My searches have failed to find a source so far. The shaft is 22 mm long and ~6 mm diameter. Connections are on the base.
The Vishay website shows similar models but could not recognise the reference number. I have contacted them.

The appearance is as here;- http://www.ebay.co.uk/itm/like/1211...f11=ICEP3.0.0&ff12=67&ff13=80&ff14=101&ff19=0
Click to expand...

357-4158-502 502 almost certainly means 50x10^2 = 5k ohms resistance. You have confirmed this with your multi-meter.

With 5V across the ends the dissipation is only 5mW.

Current 357B series are conductive plastic track devices which are smoother than wire-wound and less prone to cracking than carbon.

It is almost certain to be a linear law type (not logarithmic). But that's easy to confirm; turn to the middle and the voltage on the output should be half that on the ends.

Most single turn pots have a similar angle of rotation (note that there is a dead band at either end).

Almost any sealed pot that physically fits and meets the above is likely to work.

NB Shafts that are too long can be cut down, but try to reduce the vibration caused by cutting reaching the mechanism . Support between the pot and cut if you can.

It's possible some form of calibration may be needed even if it's just finding the centre of the pot.
 
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I sense another business opportunity Graeme.
Selling a repair kit comprising of a potentiometer, a piece of stainless rod, a stainless sleeve with two tapped holes, two grub screws thus enabling the shaft to be extended and instructions.
 
A selection of apx 6mm dia 5k linear pots with shafts at least 22mm long.
http://uk.farnell.com/jsp/search/browse.jsp?N=2031+204275+731+502+110156873+110103154+110190129+110131914+110200916+110416939+110443011+110442974+110417363+110572007+110195732+110416794+110417369+110416940+110416631+110417496+110416491+110417083+110418145+110417499+110578276+110417368+110416793+110442975+110416943&Ns=P_PRICE_FARNELL_UK%7C0&Ntk=gensearch&Ntt=potentiometer&Ntx=mode+matchallpartial&locale=en_UK&appliedparametrics=true&getResults=true&suppressRedirect=true&isRedirect=&originalQueryURL=/jsp/search/browse.jsp%3FN%3D2031%2B204275%2B731%2B502%26Ntk%3Dgensearch%26Ntt%3Dpotentiometer%26Ntx%3Dmode%2Bmatchallpartial%26No%3D0%26getResults%3Dtrue%26appliedparametrics%3Dtrue%26locale%3Den_UK%26divisionLocale%3Den_UK%26catalogId%3D%26skipManufacturer%3Dfalse%26skipParametricAttributeId%3D%26prevNValues%3D2031%2B204275%2B731%2B502
 
The original has turret connections but I could probably squeeze in side ones.

There is a locating spigot but if a replacement came without, it would succumb to twiddling.

The shaft length is the critical one but not insuperable.
 
JohnGC said:
357-4158-502 502 almost certainly means 50x10^2 = 5k ohms resistance. You have confirmed this with your multi-meter.

With 5V across the ends the dissipation is only 5mW.

Current 357B series are conductive plastic track devices which are smoother than wire-wound and less prone to cracking than carbon.

It is almost certain to be a linear law type (not logarithmic). But that's easy to confirm; turn to the middle and the voltage on the output should be half that on the ends.
Click to expand...

I am sure it will be linear as otherwise if log, it would need a centre zero with log each side!

Most single turn pots have a similar angle of rotation (note that there is a dead band at either end).
Click to expand...

The shaft rotates continuously with no stop.

Almost any sealed pot that physically fits and meets the above is likely to work.

NB Shafts that are too long can be cut down, but try to reduce the vibration caused by cutting reaching the mechanism . Support between the pot and cut if you can.
Click to expand...
It is a negative cut needed at the moment!

It's possible some form of calibration may be needed even if it's just finding the centre of the pot.[/QUOTE]
 
I have got through several of these over the years. My unit is mounted on deck and it lasts about 3 years since it's not designed for outside use. However I do protect it as best I can.
The readings for a working unit should be...
Red/green 5kohm +/- 5%
Blue/green 1.66kohm anticlockwise to the stop
3.3 kohm clockwise to the stop

This info from Raymarine many years ago. Hope of some use.
 
JohnGC said:
Sorry, I don't understand. I thought you needed a shaft 22mm long. The one's in my link range from 22mm to 50.8mm with diameters from 6.0 to 6.35mm. What did I miss?
Click to expand...

No, you are quite right. I was put off by the side connections but I think they will fit.

It would be nice to have an identical replacement (although I can't really justify that!)
 
Graham_Wright said:
No, you are quite right. I was put off by the side connections but I think they will fit.

It would be nice to have an identical replacement (although I can't really justify that!)
Click to expand...

Some of them have bottom connections.

If you go for one with PCB style solder lugs you may need some extra strain relief; some carefully applied glue for example.
 
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