My fluxgate compass works fine at power up each weekend but after about 2-4 hours the compass shuts down. The "no compass" alarm triggers as well as the "no heading" alarm. Once this happens the fluxgate won't restart unless its been off for a while (typically overnight or during the week). The batteries are fully charged and this occurs while at dockside. Any thoughts on what might cause this behavior?
Raymarine Fluxgate Shuts Down
- Thread starter Monterey385
- Start date
It sounds like you might have a thermally intermittent component on your fluxgate compass PCB. You might be able to confirm that with some freeze-it spray, but that would only tell you what you already know; your compass is failing.
I agree with JackDaw, something is heating up. Check the easy stuff first, connections to the AP computer and any splices in the wire between the fluxgate and computer. If that all checks out then you are looking at replacing the fluxgate. Don't thing there is any way to crack the case and peek inside.
I should have mentioned that this same issue occurred with a second fluxgate ... I'm thinking it might be something in the DC circuit. Would a switch going bad create this type of symptom?
A small short in the wiring, a loose connection or like you suggest a failing switch might create the symptoms. Since the problem repeatedly defaults to the fluxgate compass I would start by tracing the wiring from it all the way back to the control unit. Check connectors. The chances of two fluxgate units failing in a similar fashion over a short period of time are not very good so if nothing is found in the wiring I would start to suspect the control unit. How old is the autopilot?
Agree with Benny, two failing in the same fashion is not likely.
the control computer does have to source lots of current to drive the AP motor so it makes sense that something is getting hot in the control computer and effecting the fluxgate circuit.
Again check the connections at the unit. Perhaps the heat is coming from the motor connectors and cleaning them up will keep things cool enough for the problem to go away.
the control computer does have to source lots of current to drive the AP motor so it makes sense that something is getting hot in the control computer and effecting the fluxgate circuit.
Again check the connections at the unit. Perhaps the heat is coming from the motor connectors and cleaning them up will keep things cool enough for the problem to go away.
Normal electronic treubleshooting procedures
If you can make it fail, be happy, you're almost there. While in the failed condition, measure power and grounds with a voltmeter. If you are unable to see a fault and the system is still inoperative, you have eliminated that as a source of the problem. If it is a power or ground problem, chase it. Be sure to be on the lookout for corrosion. Corrosion can cause low voltage or outright open circuits when they heat up due to resistance of the corroded connection. Sometimes it's just easier to replace connectors because you can't see the corrosion.
If it's on a circuit board, I absolutely agree that freeze spray could help locate a faulty component, but it isn't really just telling you to throw it away. Individual components are usually really cheap. Just replace the bad resistor, capacitor, transistor, or whatever. I realize this may be dough for a novice, but it isn't impossible.
In today’s world, there is no excuse for anyone to not have a functional multimeter.
One example
http://www.harborfreight.com/7-function-digital-multimeter-90899.html
Or if you are also interested in chasing AC problems
http://www.harborfreight.com/clamp-on-digital-multimeter-95683.html
No connection with the company, it’s just cheap.
Ken
If you can make it fail, be happy, you're almost there. While in the failed condition, measure power and grounds with a voltmeter. If you are unable to see a fault and the system is still inoperative, you have eliminated that as a source of the problem. If it is a power or ground problem, chase it. Be sure to be on the lookout for corrosion. Corrosion can cause low voltage or outright open circuits when they heat up due to resistance of the corroded connection. Sometimes it's just easier to replace connectors because you can't see the corrosion.
If it's on a circuit board, I absolutely agree that freeze spray could help locate a faulty component, but it isn't really just telling you to throw it away. Individual components are usually really cheap. Just replace the bad resistor, capacitor, transistor, or whatever. I realize this may be dough for a novice, but it isn't impossible.
In today’s world, there is no excuse for anyone to not have a functional multimeter.
One example
http://www.harborfreight.com/7-function-digital-multimeter-90899.html
Or if you are also interested in chasing AC problems
http://www.harborfreight.com/clamp-on-digital-multimeter-95683.html
No connection with the company, it’s just cheap.
Ken
There really is not a ton to go wrong with a Fluxgate and they usually either work or don't. In my experience the problem is most often in the course computer. You can test the fluxgate easily. The CC would need to go back to Raymarine..
Set DVM to:
Red to Yellow = 4Ω
Green to Yellow = 8Ω
Screen to Blue = 8Ω
Any other combination of wires = Open Circuit
Set DVM to:
- 200 ohm scale
- Disconnect the transducer from course computer
- Take measurements (a +/- 2Ω reading is okay)
Red to Yellow = 4Ω
Green to Yellow = 8Ω
Screen to Blue = 8Ω
Any other combination of wires = Open Circuit
Update:
About a five weeks ago the autopilot began reporting no compass consistently. Tested old compass using the Ohm test from Maine Sail. All readings checked out. Tested red and bare for volts ... 2.4 volts at the smart pilot. Bought new Fluxgate ... Same problem.
Checked fuses on smart pilot board ... All good.
Checked inbound voltage on smart pilot ... 13.2 volts.
Checked voltage on rudder reference terminal ... 4.1 volts.
Should the smart pilot reduce voltage to the Fluxgate and rudder reference to this degree?
If not, is there anything else I can check?
Seems like I should probably ship the board to Raymarine.
About a five weeks ago the autopilot began reporting no compass consistently. Tested old compass using the Ohm test from Maine Sail. All readings checked out. Tested red and bare for volts ... 2.4 volts at the smart pilot. Bought new Fluxgate ... Same problem.
Checked fuses on smart pilot board ... All good.
Checked inbound voltage on smart pilot ... 13.2 volts.
Checked voltage on rudder reference terminal ... 4.1 volts.
Should the smart pilot reduce voltage to the Fluxgate and rudder reference to this degree?
If not, is there anything else I can check?
Seems like I should probably ship the board to Raymarine.
I meant to close this out with the final resolution. The computer and fluxgate were shipped to Raymarine and both worked fine on the bench. Traced the issue further to a run of fluxgate wire that had failed (it had two splices between the helm and the bilge). Once the failed section of fluxgate wire was bypassed, the fluxgate works fine.