False alarms on ST6000 series Auto pilot

[john_morris_uk]

Our auto pilot has developed an annoying intermittent fault.

We have a Raymarine Course Computer with rate gyro plus an ST 6000 Series low profile control unit flush mounted in the cockpit. It’s worked perfectly for many years. A few days ago it started beeping saying ‘Battery Low’. The battery voltage is 12.7 or maybe as low as 12.5 on the Raymarine system check so I though it might be a dirty connection in the Seatalk bus to the control head. Even while the alarm is sounding there’s still 12.5 v at the control head and similar at the course computer.

Any ideas? The only conclusion I’ve come to is that the control head has gone faulty. (I’m assuming that the low voltage measurement is in the control head and not in the course computer.

(I’ve replaced the connectors and checked continuity and even double checked the voltages while the system is drawing heavy current to the motor on the rudder stock. It varies by a fraction of a voltage as one would expect.)

The only saving grace is that it carries on working but bleeps all the time. It’s driving me mad and I can’t stand hand steering for hours and hours and we’ve got a channel crossing in the next day or two.

 

[NorthUp]

wild guess- could there be a battery on a pcb to retain settings when turned off?

 

[john_morris_uk]

wild guess- could there be a battery on a pcb to retain settings when turned off?

There might be, but the manual says ‘low battery’ means you should start your engine and recharge your batteries so that implies the low battery refers to the supply voltage.

 

[superheat6k]

You may want to read this ...

https://www.dropbox.com/s/cdlabidtequ88jt/Autohelm 100 Low Voltage Fault resolve.pdf?dl=0

The diode suggested is easy enough to obtain, but if your stuck I probably have one in my workshop that will suffice.

Best of luck.

 

[john_morris_uk]

You may want to read this ...

https://www.dropbox.com/s/cdlabidtequ88jt/Autohelm 100 Low Voltage Fault resolve.pdf?dl=0

The diode suggested is easy enough to obtain, but if your stuck I probably have one in my workshop that will suffice.

Best of luck.

Brilliant. Symptoms don’t quite match as ours keeps steering and doesn’t disengage the clutch etc but it’s a definite maybe on the hunt for a solution. Thank you for the offer of a. 1N4001 but I’ve got a selection of diodes in the 1N series in the workshop at home. We’re in Alderney ATM so I might even try and find one locally.

 

[john_morris_uk]

The joys of Alderney. Mainbrayce say their engineer might have a diode but he’s not in today.

Nowhere else on the island seems to have a diode.

Hey ho - ten hours of beep beep ‘low battery’ false alarm or hand steering tomorrow.

Raymarine said we should consider buying a new autopilot. I note that an EV-100 without motor drive unit (our old one is fine) but with gyro and control head start at around £1k...

 

[Keith-i]

Have you tried London House or the hifi/music shop in Victoria Street? There was also a chap who repaired electrical items but I can't remember his name off-hand. Shame I didn't know of your problem last week as I was over visiting my parents and might have found something in my collection of bits.

 

[john_morris_uk]

Have you tried London House or the hifi/music shop in Victoria Street? There was also a chap who repaired electrical items but I can't remember his name off-hand. Shame I didn't know of your problem last week as I was over visiting my parents and might have found something in my collection of bits.

London House says they have no components. If I get up to Victoria St again I’ll ask around.

 

[ithet]

You may want to read this ...

https://www.dropbox.com/s/cdlabidtequ88jt/Autohelm 100 Low Voltage Fault resolve.pdf?dl=0

The diode suggested is easy enough to obtain, but if your stuck I probably have one in my workshop that will suffice.

Best of luck.

I have the same issue with an ST4000, and from the web I see it is common. The ST4000 does not use the Type 100/300 course computer referred to above, as it has the computer built into the display head itself. If you or anyone else are able to apply a similar diode fix to a ST4000 I would be interested to know the details and photos of the circuit board please.

(See OP has 6000+ which does use separate computer)