1980's Autohelm 5000

[Sun-Kist]

I have an old Autohelm 5000 and need to disassemble the control unit to check for a slipping gear.

I have it in front of me, but can't figure out how to open the unit without risking damage.

Anyone have advice?

Thanks in advance.

Dick

[senormechanico]

My dim memory seems to say start at the back side.
Connectors are actually mounted on a chassis of some kind.
Remove anything on the back side which rotates such as nuts.
I'm sure somebody will chime in to either confirm or shoot down.
Good luck.

[Sun-Kist]

Thanks, Steve.

I did remove two plastic nuts that hold the connectors in place on the back of the unit.

The face apparently separates from the rest of the "box". When I gently pry at the seam between face and box, I can tell there are connectors holding the pieces together.

However, I dare not pry hard enough to risk breaking the connectors, and I can't safely pry it apart enough to see what type of connectors are attaching the two pieces.

Hopefully, someone with direct experience can guide me. I'm sure it's simple, but I hate to break things.

[DeepFrz]

Do you need to take the 3 switch faces off? Are there set screw in the long part of the finger grip. Can't tell from the picture. There may be nuts underneath that hold the face plate on.

[Capn Dan]

On the back you will see two connector plugs. Next to those plugs is an indentation with a plastic "nut". The nut should have two small holes in it. Use a pair of snap ring pliers to unscrew the nut.

The drive that couples with the "steer" shaft often slips. Replace the rubber bushing and it should work.

You do not need to remove any of the knobs on the front.

[Capn Dan]

Dick,

Once you get it open, look on the circuit board below the compass for a film or residue. This is one of the few Autohelm / Raymarine units that used an oil filled compass and yes, they do occasionally leak.

Dan

[Sun-Kist]

Dan,

Many thanks for the great info. You mention replacing the "rubber bushing". I don't see a bushing, per se, but are you referring to the thin rubber belt that is shown in the attached photo?

Also, call me dense, but I don't know which device is the compass, i.e. is it the black upright cylinder that has the belt to the steer shaft, or is it the horizontal metallic cylinder that is connected to the steer shaft?

When I turn the steer control, the black cylinder moves without any slippage, but when I turn the cylinder, the shaft doesn't move. I don't know whether the cylinder drives the shaft or vice versa.

Lastly, there is no sign of any film or residue anywhere on the circuit board - hopefully that's a good sign.

Dick

[Capn Dan]

Dick,

The black cylinder is the compass. When you turn the steer knob, the compass should turn. Turning the compass will not turn the steer knob.

Now for the bushing. In the upper left corner of your photo the gold colored cylinder is a motor. When the autopilot wants to make a course correction, it activates the motor and that turns the steer shaft and thus the compass. The rubber bushing that couples the motor to the steer shaft is located inside the steer shaft next to where the big oring connects on the steer shaft. This bushing has to slip when you turn the steer knob, but not slip when the motor turns. Thus, they wear out.

To test it, leave the case off, reconnect the cables and turn the AP on. Now rotate the control head and the motor should kick in and rotate the compass. Try moving the head in both directions as it may only slip in one direction.

Yes, this is a very different AP, unlike any other that Autohelm made.

Dan

[Sun-Kist]

Dan,

I'll follow your test directions when I get back to the boat (probably Sat.)

Assuming I replace the bushing (seems like it may be smart no matter the test outcome), any suggestions on sourcing a new one, or is it a "standard" type?

Continuing THANKS for your detailed knowledge/replies,

Dick

[Capn Dan]

Dick,

In my last reply, I made a mistake. To test it, use your remote control. Try both directions. If the motor can turn the compass both directions, I would leave the bushing alone.

Sorry about the error, it has been awhile since I have worked on one of these.

Also, why do you suspect a problem in the control head?

Dan