Raymarine Auto Pilot

[Thinksnow]

Help please: 2002 Hunter 306 with original Raymarine instruments. This happened end of last season (2024) - went hard over on the wheel which caused the ‘Rotary Rudder Reference Transducer’ for the Auto Pilot to dislodge from it's mount & the rudder readout on the Raymarine Smart Pilot went all the way to port and froze there. I re-installed the transducer unit below deck to the rudder assembly, but it didn’t work- not sending signal to the Smart Pilot (double checked all wiring). A Raymarine tech said to verify the transducer wasn’t working by doing a resistance test specified by Raymarine. I did that, and verified damage to transducer. I ordered a new Transducer unit, did the same resistance test to verify it was working properly, then installed as per specs. Turned everything on… it worked for about 5 minutes then suddenly the rudder position readout went all the way to starboard this time, and stopped working - again no signal to ‘Smart Pilot’ readout. Repeated the resistance test on this new unit, and it now failed. Does anyone have any idea why? I don’t want to buy another $400 transducer unit and blindly try again. Is there something wrong along the line that is ‘shorting out the transducer??
Thoughts appreciated ~ cheers

Michael

Raymarine ST60+ Wind,Speed,Depth
Raymarine ST6002 Smart Pilot system
Raymarine Rotary Rudder Reference Transducer

 

[Tally Ho]

No Good suggestions, but is there any way that the drive wires to the AP motor, or the wires for the rudder sensor are wired backwards? I hooked up a new AP, and accidentally wired the drive motor “backwards”….

So when I took her for a sea trial, she started out holding course, but as the computer called for STB rudder, the motor turned the wheel to Port. And the more the computer called for STB rudder, the harder she turned to port.

I did a few crazy Ivan’s in the bay before I figured out what was happening.

Also, is the geometry for the sensor still OK when you remounted the sensor? 90 degrees when wheel is centered? And reading 0 rudder angle at the display?

Greg

 

[Jan_H]

It sounds like a a broken 5V or Gnd wire, or a short between the transducer centre tap and either 5V or Gnd - this would cause the readout to show one or other limit. The transducer is just a 5kOhm potentiometer that you can get from Digikey/Mouser/Newark for $3 and hook up instead of a Ray unit for testing purposes, and check that this is all working correctly with a multimeter. The connections to the transducer are +5V (red) and 0V (grn) to the ends of the potentiometer, and the centre tap is the blue terminal. The voltage at the centre tap should be 2.5V in the rudder centered position, and change from about 2V to 3V over the wheel/rudder range. If the AP behaves properly with the test potentiometer, then the problem is most likely in the wire between the AP and the rudder ref transducer.
Hope this helps.
Jan

 

[colemj]

When you replaced the transducer, did you home-run the cable from it straight to the AP, or is there a section of existing cable you connected to? If the latter, then check there.

Mark

 

[Thinksnow]

No Good suggestions, but is there any way that the drive wires to the AP motor, or the wires for the rudder sensor are wired backwards? I hooked up a new AP, and accidentally wired the drive motor “backwards”….

So when I took her for a sea trial, she started out holding course, but as the computer called for STB rudder, the motor turned the wheel to Port. And the more the computer called for STB rudder, the harder she turned to port.

I did a few crazy Ivan’s in the bay before I figured out what was happening.

Also, is the geometry for the sensor still OK when you remounted the sensor? 90 degrees when wheel is centered? And reading 0 rudder angle at the display?

Greg

Thanks for the reply. I didn’t have to touch the wires to the AP motor. Only the wires going directly from the transducer to the activator (computer). And yes the geometry for the sensor was accurate. Good points, but still researching for the answer !

Michael

 

[Thinksnow]

When you replaced the transducer, did you home-run the cable from it straight to the AP, or is there a section of existing cable you connected to? If the latter, then check there.

Mark

The cable goes straight from the transducer to the rudder input on the activator (computer). Essentially I just replaced the old with the new. Thanks
Michael

 

[Thinksnow]

It sounds like a a broken 5V or Gnd wire, or a short between the transducer centre tap and either 5V or Gnd - this would cause the readout to show one or other limit. The transducer is just a 5kOhm potentiometer that you can get from Digikey/Mouser/Newark for $3 and hook up instead of a Ray unit for testing purposes, and check that this is all working correctly with a multimeter. The connections to the transducer are +5V (red) and 0V (grn) to the ends of the potentiometer, and the centre tap is the blue terminal. The voltage at the centre tap should be 2.5V in the rudder centered position, and change from about 2V to 3V over the wheel/rudder range. If the AP behaves properly with the test potentiometer, then the problem is most likely in the wire between the AP and the rudder ref transducer.
Hope this helps.
Jan

Thanks for the reply. Pardon my lack of knowledge but what is the ’centre tap’ ?

Michael

 

[Jan_H]

The centre tap on a potentiometer is also referred to as the wiper terminal - the voltage on this changes as the potentiometer shaft rotates - this is the feedback signal the 'course computer' uses to control the rudder position. Do you have a Type 100 course computer? if so, the four rudder ref. connections are screen (grey), +5V (red), 0V (green) and centre tap/wiper/position signal (blue).
Jan

 

[Rich Stidger]

It sounds like the rudder transducer is being damaged by the extreme AP movement. I don't believe that should happen. I think the AP should be able to drive to either port or stbd stop without damage.
But to your original issue with the AP spontaneously driving to a stop- I had the same experience with my ST7000 AP on a ST50 system. You have a ST60 system, so this may not apply. For my AP doing a hard turn without warning. Raymarine told me that a firmware update was needed in the AP controller. I sent it off on a Monday and had it back on Thursday. No charge. And the problem never reoccured.

 

[Thinksnow]

It sounds like the rudder transducer is being damaged by the extreme AP movement. I don't believe that should happen. I think the AP should be able to drive to either port or stbd stop without damage.
But to your original issue with the AP spontaneously driving to a stop- I had the same experience with my ST7000 AP on a ST50 system. You have a ST60 system, so this may not apply. For my AP doing a hard turn without warning. Raymarine told me that a firmware update was needed in the AP controller. I sent it off on a Monday and had it back on Thursday. No charge. And the problem never reoccured.

Thanks for the reply. The hard over was ‘operator error’ not the AP.
Michael

 

[Rich Stidger]

Thanks for the reply. The hard over was ‘operator error’ not the AP.
Michael

Regardless, the rudder should have hard stops, and the transducer should not be damaged when the rudder is driven or steered to these stops.
Now if there are no hard structural stops, then I think that condition is a design/mfg defect.

 

[Thinksnow]

Regardless, the rudder should have hard stops, and the transducer should not be damaged when the rudder is driven or steered to these stops.
Now if there are no hard structural stops, then I think that condition is a design/mfg defect.

Point taken, you are right. There are hard stops P & S. Which leads me to wonder how the transducer dismounted in the first place, resulting in it’s damage and replacement… then the new transducer failing within the first 5 minutes , and how the physical damage originally done relates to this replacement transducer’s failure
Michael

 

[Rich Stidger]

@Thinksnow ,
Exactly how is the rudder transducer being damaged? Is is physically broken or electrically faulty. Pictures might help.

 

[Thinksnow]

It became dislodged at the base, but still attached to the rudder by the ball joint on its articulating arm. The transducer had no apparent physical damage. (It had been mounted on a wooden block that was glued to the under deck, factory installation). The arm still had the resistance spring in it when I remounted it, and appeared physically normal. The readout from the AP though remained frozen to port, even when rudder was turned at this point. That’s when the Raymarine tech said to check with a multimeter the resistance on the transducer, and explained how it should register. It failed the test, so he said it was shot. I purchased & installed a new transducer which registered rudder position accurately on the AP for about 5 minutes, then abruptly shut down (”no rudder input” on the AP screen), the rudder position now frozen to starboard. I did the same resistance test & it now failed. That’s why I’m lost as to the connection between the original transducer dislodging & apparent internal damage, and the new transducer failing after it was installed & wired to the computer as per instructions.
This picture is of the original transducer in position as I’m about to remounted it , and then re-connect ball/arm to the top of the rudder on right..

 

[Rich Stidger]

Lots of questions-
Precisely, how did the original transducer come loose? Did the round base become loose from the square mounting block, or did the mounting block come loose from the under deck?
What do you mean by "resistance spring"?
The base of the transducer is attached to the mounting block by two screws in slots. Is it possible that the transducer could have been remounted 180 degrees from original?
How did the Raymarine tech instruct you to test the transducer? What were the steps?

From your picture, I can't tell if the rudder is in the centered position nor if the transducer is also in the centered position. I do see that the wire from the transducer exits at 3 o'clock while the transducer arm is at 11 o'clock. That suggests to me that the transducer as pictured is not at center.
Look at the picture below of my transducer. In this picture the rudder is centered and the transducer is centered. Note that the transducer wire exits at 6 o'clock and the arm is at 12 o'clock. I think the relationship between the wire and the arm will indicate where the wiper in the transducer is located.

 

[colemj]

When your transducer is mounted as it originally was, are you sure that both the tiller arm and the drive cylinder don't physically hit it when hard over?

The back of the Raymarine transducer has two index marks that align when its wiper is centered.

The transducer has no spring, and it should not be able to move more than ~45* max from each side of center before it is stopped internally.

If yours was installed off center like your picture, then it is possible you broke through that internal stop when hard over and the wiper is no longer operating.

Mark

 

[Thinksnow]

Lots of questions-
Precisely, how did the original transducer come loose? Did the round base become loose from the square mounting block, or did the mounting block come loose from the under deck?
What do you mean by "resistance spring"?
The base of the transducer is attached to the mounting block by two screws in slots. Is it possible that the transducer could have been remounted 180 degrees from original?
How did the Raymarine tech instruct you to test the transducer? What were the steps?

From your picture, I can't tell if the rudder is in the centered position nor if the transducer is also in the centered position. I do see that the wire from the transducer exits at 3 o'clock while the transducer arm is at 11 o'clock. That suggests to me that the transducer as pictured is not at center.
Look at the picture below of my transducer. In this picture the rudder is centered and the transducer is centered. Note that the transducer wire exits at 6 o'clock and the arm is at 12 o'clock. I think the relationship between the wire and the arm will indicate where the wiper in the transducer is located.
View attachment 229655

- the wood mounting block came loose from the under deck, the transducer still attached.
- disregard the spring comment , for some reason I’d thought it was spring loaded. (the boat is on the hard, under its cover & surrounded by 4’ of Ontario snow so I haven’t access at the moment).
- I had taken pictures for reference of the transducer position in relation to the mounting block & the under deck to ensure it was mounted in original position. I did the same for the install of the new transducer using the same mounting holes for base & arm.
- see the screen grab below of the post that the Raymarine tech referred me to for the resistance test.
- the picture I shared was before I re-installed everything. When the re-installation was done, rudder was centred with the transducer arm at 12 o’clock, the wire was at about 5 o’clock I recall.
thanks for your observations….

 

[Thinksnow]

When your transducer is mounted as it originally was, are you sure that both the tiller arm and the drive cylinder don't physically hit it when hard over?

The back of the Raymarine transducer has two index marks that align when its wiper is centered.

The transducer has no spring, and it should not be able to move more than ~45* max from each side of center before it is stopped internally.

If yours was installed off center like your picture, then it is possible you broke through that internal stop when hard over and the wiper is no longer operating.

Mark

Good question… yes, I made sure there was no contact when hard over.
Disregard the spring comment, for some reason I thought it was spring loaded.
The photo shows me just holding over the original mounting position for rough reference. When re-installed, the arm was at 12 o’clock & the wire came out at about 5 o’clock. I made sure it was mounted exactly as it had been before troubles began. I’ve owned the boat for 8 years & never had a problem with the AP before this.
Thanks for your input… any more thoughts appreciated
Michael

 

[Rich Stidger]

Do you have the results of the resistance measurements on the original transducer and the replacement unit?

 

[Thinksnow]

Do you have the results of the resistance measurements on the original transducer and the replacement unit?

The results from the original damaged unit ranged between sporadic and no reading. The new unit read within the recommended parameters before it was installed, with smooth transitions when turning the wheel S to P to S. Then after installed & subsequent break down, matched the original damaged unit.