Raymarine linear drive type 1/Acu-200 issue.

[Rogsails]

Edit : I only have 7 volts at the A B power connections on the acu-200 when the wires are unplugged and when the wires are connected and auto is selected on the display more like 2-5 volts.

I have an issue with my Raymarine linear drive type 1. It started making a lot of nose the last few hours of operation and now it won’t turn the wheel and just makes a loud sound like it’s turning to turn the rudder but can’t.

I opened the unit up there was a lot of dust inside maybe from the gears or motor. The gears all look fine and turn without issue fine but not sure I know what to look for. I removed the motor and connected to 12v power and it seemed to run fine with out excessive sound.

[Rogsails]

I found this troubleshooting guide on the raymarine site it may help
Someone else. It’s Pasted below

Looks like the clutch is shot or just the circlip that hold the clutch coil assembly in place it seems to have worn on second inspection. Also the motor isn’t moving the ram





“” Testing an autopilot mechanical linear or rotary drive unit
How do I test my drive unit to see if it's working?
When an autopilot fails to move the rudder, the fault may be in the autopilot course computer, drive unit, or rudder reference transducer.

First check the correct operation of the rudder reference unit:
Move the rudder to the central position and then turn the wheel to Starboard- the rudder angle display on the Autopilot control unit should show the rudder moving to Starboard (green) repeat the test turning the wheel to Port and the display should indicate rudder moving to port (red). if correct, then the rudder reference is operating correctly. If the opposite is displayed then the connecitons need to be changed
To correct this installation error:
1) disconnect the rudder reference transducer's green lead which had been connected to the green Rudder terminal of the ACU or autopilot course computer and instead connect the green lead to the ACU's or autopilot course computer's red Rudder terminal terminal.
2) disconnect the rudder reference transducer's red lead which had been connected to the red Rudder terminal of the ACU or autopilot course computer and instead connect the red lead to the ACU's or autopilot course computer's green Rudder terminal terminal.
If the rudder reference unit still displays incorrectly, then test the transducer as follows
Disconnect the rudder reference unit from the course computer
Using a multimeter set to test resistance test as follows

Red to Green: 5K Ohms (+/- 10%) Steady
Red to Blue: Variable no less than 1.5K no more than 3.5K as the wheel is spun hardover to hardover.
Blue to Green: Variable no less than 1.5K no more than 3.5K as the wheel is spun hardover to hardover.

The Red to Blue and Blue to Green may not go all the way to 1.5K or up to 3.5K, but when the wheel is at midships, the deflection should be about equal in either direction(i.e. midships 2.5K if it goes up to 3.1K, it should go down to around 1.8)
Should the resistance measurements for the rudder reference transducer not be as specified above, then the rudder reference transducer should be replaced. Raymarine's part number is M81105.
When using a rudder reference transducer, it is also very important to ensure that rudder limits have been correctly configured to establish angular limits to the amount of rudder travel and to ensure that the rudder angle indicator correctly indicates the position of the rudder with respect to the centered position.

The next step is to test the drive itself
Mechanical drive units feature reversible DC motors, inside the motors are carbon brushes, the drives also have an electromagnetic clutch, epicyclic gearbox and belt drive.

The clutch of a mechanical drive unit is tested by placing the autopilot into AUTO and checking the steering wheel becomes 'locked', then selecting STANDBY will release the clutch and the wheel should become free to turn by hand.

A properly functioning mechanical drive until will engage the clutch (causing the drive to appear locked) when 12 VDC is present across the clutch leads. Similarly, a properly functioning drive until will release the clutch (causing the drive to disengage from the steering system) when 12 VDC is not present across the clutch leads.

Accordingly, a clutch related problem may be fault isolated by measuring voltage across the Clutch terminals of the ACU or course computer. When the autopilot is in Standby mode, the measured voltage across the clutch terminals should be 0 VDC. When the autopilot is in Auto or Track modes, the measured voltage across the clutch terminals should be 12 VDC. Note that even 24v Raymarine drives operate on a 12v clutch, some 3rd party drives use a 24v clutch and so be sure to check the correct voltage required by the drive.

If there is correct voltage present at the clutch terminals on the computer or ACU, but the clutch still fails to operate, check the wiring to the drive unit, if all OK, then connect 12v direct to the clutch wires at the drive unit, if the clutch fails to operate, then the drive is faulty and needs to be serviced.
If there is not the correct voltage present at the clutch terminals on the computer or ACU, then the computer or ACU is faulty and needs to be serviced.

Should the clutch be operating correctly, the issue could be the DC motor within the drive unit, this can be tested by the drive unit's ability to move the rudder in each direction when driven by a source of power other than the autopilot course computer. To do so, centre the rudder, disconnect the drive unit's motor leads from the autopilot course computer's / ACU's MOTOR terminals and select AUTO to energise the clutch, then momentarily connect them to the course computer's / ACU's power terminals.
This connection should be momentary in nature and only long enough to verify that the drive is able to move the rudder. After verifying movement of the rudder in one direction, center the rudder again, reverse the motor wires polarity on the computer's/ ACU's power terminals and verify the drive moves the rudder in the opposite direction.

Should the drive unit move the rudder in both directions, then the fault has been isolated to the autopilot's course computer, necessitating that it be serviced or replaced. Should the drive unit move the not rudder in both directions, then the fault has been isolated to the drive unit, necessitating that it be serviced or replaced.

Should the operation of the motor be erratic, sometimes moving the rudder and sometimes not, this could be sticking or worn brushes inside the motor, which will need to be replaced through servicing.””



Exploded diagram of the drive unit linked below




http://forum.raymarine.com/attachment.php?aid=609

[CaptainRivet]

loud sound of type 1 linear drive is 99.9% the plastic gearing converting round to vertical motion, that no 14 and 15 but order 13-16. makes sense if you have it open to exchange no. 16 belt too even if its viusally ok. if its not the gearing its the clutch 5-10 but thats more seldom.


number 2 ACU: check connecting cable and fuse. most likely that ACU is toast and because the clutch could not disconnect due to that the gearing lost serveral tooth. classic fail combo.

[deblen]

This vid & others on Youtube may help. Raymarine M81130 type 1 linear drive

https://www.youtube.com/watch?v=1UL94hMh3qs

https://www.youtube.com/watch?v=74Py-lzS8YM

[smac999]

you will only have voltage if the unit is trying to turn. just because it's in auto doesn't mean it's turning. hit auto and do a 40* course change. then measure

without a drive I think 7v is normal. it's a saftey feature with no load. I was told this by raymairine last year while testing one. but you should have 7-12v with the pump trying to pump.

check input voltage while it's trying to pump and make sure it's not droping much. and also check the pump current. if it's bad and shorting out you'll have high amps and low volts.

[CaptainRivet]

Originally Posted by smac999

you will only have voltage if the unit is trying to turn. just because it's in auto doesn't mean it's turning. hit auto and do a 40* course change. then measure

without a drive I think 7v is normal. it's a saftey feature with no load. I was told this by raymairine last year while testing one. but you should have 7-12v with the pump trying to pump.

check input voltage while it's trying to pump and make sure it's not droping much. and also check the pump current. if it's bad and shorting out you'll have high amps and low volts.

Its an electric linear drive, so motor and no pump there.
Yes you need to meassure voltage during operation, thought thats clear.
But he need to first fix the lineardrive to be able to do the tests with the ACU.