Raymarine Clutch Won't Engage - Help!

[Cat_A_Tonic]

Hi All, any information here would be a great help. I have a type 1 linear drive and the clutch does not want to engage on it.

On occasion it will, then everything works fine. But lately it seems to not work at all. I have dissasembled the unit, ensured that the clutch is free to move, no corrosion issues. I ran a new thicker guage wire from the control unit to the drive, didn't help.

I checked the voltage from the control unit, 8 volts to the clutch when you hit 'track'. Not sure if that's correct or not but nothing happens.

I'll continue to bench test but just wondered if this is a common issue. Do the magnets wear out in the clutch? Seems unlikely.

Thanks!
Chris

[noelex 77]

The clutch failed on my drive following a lightening strike. It is just a coil of wire acting as an electromagnet. Mine was open circuit so the was a break in the wire somewhere.(use your multimeter on the resistance scale the result should be about 40 ohms from memory)
It should be simple to replace. I would be interested in the cost if you find out. I have replaced my whole drive unit, but want to repair the old as a spare.

[Cat_A_Tonic]

According to a Raymarine service reply to another similar issue:

Answer

the drive arm should be getting 12v to the clutch. I tested the ohm's on the meter and it seemed ok, like 30 or so.

In bench testing the drive arm, I applied 12v to the clutch and it engages instantly every time.

Looks like the issue is at the computer, only putting out about 8 volts.
Next steps are to ensure the 12v supply to the drive computer are solidly connected. If that's not it I may be out of luck, having to replace the computer.

Thanks.
-Chris

[noelex 77]

Yes unfortunately it sounds like your problem is with the computer /core pack. Be aware that you may also have to replace the display unit if the core pack is changed.
A relay to engage the clutch from the 8v supplied by the core unit may be a cheap option, but given this fault I would be reluctant to depend on long term reliability of such a solution.

[Cat_A_Tonic]

The issue was that I am an idiot. There was a separate 12v switch for the auto pilot main unit that was not being switched on. It was a little deceiving in that it did power on though, but as it turns out it was getting 12v via the Sea Talk Cable, coming from the GPS. Had it not powered on at all I would have suspected power rather than a faulty drive arm. Anyway I guess the low amp current coming through the seatalk cable was enough to engage the drive arm sometimes, but not often.

To correct I removed the 12v wire from the seatalk connection to the drive unit since I think sea talk is not supposed to have 2 sources of power, then of course turned the 12v power switch on.

Works like a champ now.
Thanks everyone who posted.

-Chris

[scotte]

Don't feel dumb! Our boat is the same way - when the autopilot was replaced by a previous owner, they put the switch on a new hidden breaker down in the engine room (just barely within reach from the cockpit, if you know where to feel for it). Not the least bit obvious - and meanwhile the switches at the nav station and on the main switch panel that say "autopilot" do nothing. When we were first looking at the boat, the broker was rather pleased that I found the switch, because he thought the autopilot was broken! (And he couldn't exactly ask the previous owner as he's no longer with us).