Autohelm AH4000 troubleshooting

[Mirage35]

Yes, I know it's an antique. My AH4000 has stopped operating - it seems to have power and beeps when I press buttons, but nothing happens at the wheel. Before trying to trouble shoot I wonder if anyone can help me with an apparent contradiction in the manual.

Under installation: "If the 12v supply is accidentally connected to the drive unit connection terminals permanent damage will be caused."

Under maintenance: "If the drive unit is suspected of being faulty it may be checked by connecting 12v across the sockets at the end of the drive unit cable ..."

Maybe this will become apparent to me when I burrow in to the unit and see the connections, but are there any knowledgeable people who can give me a clearer explanation to start with?

[river]

I think it means you can connect 12V to the motor directly to test it, but do not put 12V into the controller where it expects the motor to be connected.

[wingssail]

Originally Posted by river

I think it means you can connect 12V to the motor directly to test it, but do not put 12V into the controller where it expects the motor to be connected.

Exactly

[wingssail]

Originally Posted by AnglaisInHull

Yes, I know it's an antique. My AH4000 has stopped operating - it seems to have power and beeps when I press buttons, but nothing happens at the wheel. Before trying to trouble shoot I wonder if anyone can help me with an apparent contradiction in the manual.

Under installation: "If the 12v supply is accidentally connected to the drive unit connection terminals permanent damage will be caused."

Under maintenance: "If the drive unit is suspected of being faulty it may be checked by connecting 12v across the sockets at the end of the drive unit cable ..."

Maybe this will become apparent to me when I burrow in to the unit and see the connections, but are there any knowledgeable people who can give me a clearer explanation to start with?

Chances are if you're getting "beeps" etc then the control unit is probably working, but the drive unit is not, and may simply be disconnected by some wiring or corrosion problem.

So a problem diagnosis is:

• Disconnect the motor and test it with jumpers to a 12v source, reverse the jumpers and it should turn backwards.
• If the motor does not turn at first try to rotate it by hand. Sometimes some rust or salt is preventing it from running and a little help will get it going again. (if it is a tiller drive, then you "help" it by pulling on the extension rod and then pushing on it.)
• If the drive unit won't run on straight 12v, then it might be toast. It's hard to repair these but you might be able to find a replacement.
• If the drive unit works then hook up the wires to the control unit again and see if it now works (in standby, hold the +10 for a second, then the -10.
• If it still does not work, and the control unit still beeps, double check the wires, end to end.
• You might try a volt meter on the wires but I've never had to do that. I'd be cautious.

I've been using Autohelm (then Raymarine) ST4000 units for 30 years. I've never had a problem with the control units, but the drive units wear out and mostly frequently the wires get corroded and don't pass current to the drive unit.

Right now we are on our second control unit, but only because at one time several years ago when I wore out a drive unit and needed a spare the supply chain was so tight nobody had a drive unit to sell me separately, not even Raymarine in England could help. So I bought a whole unit just to get the spare ST4000GP motor. Five years later I finally installed the new control unit and X5 box but the original from 1985 was still working fine.

[Mirage35]

Originally Posted by river

I think it means you can connect 12V to the motor directly to test it, but do not put 12V into the controller where it expects the motor to be connected.

Ahhhh ... that makes sense - thank you. I was reading it backwards.

[Mirage35]

Originally Posted by wingssail

- snip -
So a problem diagnosis is:
- snip -

And thanks for the detailed procedure - it's sort of where I was going but you've given me a good head start. The contacts in the connector have been an ongoing problem, but it doesn't seem to be that this time so I'm going to take the time to work through the whole system and figure it out.