SPX 30 Drive Stop Issue

[SVNeko]

Hi, I have a hydraulic autopilot motor (Lecomble &Schmitt) that is controlled by a SPX30 computer and a P70 control head (although I mostly control the pilot from an e127). Lately, the AP has been dropping out citing "Drive Stopped". When I re-engage it it sits for a while saying "Setting to Auto" then either engages or drops. If it engages, it soon drops again, saying Drive Stopped.

At anchor I can keep it engaged for a minute and when I use it to turn the rudder, nothing happens. The rudder is free to turn, so no blockage. The rudder reference unit seems to work because the electronic rudder reference shows it turning when I manually turn the wheel. The drive seems to work because when I apply power to the motor output leads at the computer, the drive turns the rudders. So, it seems to me that the computer is faulty, but it is only a couple years old and I had it checked a year ago.

Any ideas?

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Peter,

The reported issue may be caused by any of the following:
- insufficient power provided to autopilot ... connect vessel to shore power and permit its batteries to become fully charged. After doing so, and while still connected to shore power, then test the autopilot by placing it in Auto mode. Should the problem abate, then it is recommended that the vessel's batteries and the charging system be tested. Should the symptoms persist when so tested, then perform tests of the ACU and drive unit to isolate the problem.
- autopilot course computer / actuator control unit (ACU) failure ... disconnect drive unit motor leads from autopilot course computer / ACU MOTOR terminals. Connect voltmeter to the Motor terminals and then place the autopilot in Auto mode ... the measured voltage should be approximately 7.5 volts for an autopilot course computer / ACU powered from a 12 VDC circuit or 13 volts for an autopilot course computer / ACU powered from a 24 VDC circuit. Should these values not be observed, then the autopilot course computer / ACU should be sent to Raymarine’s Product Repair Center to be bench checked / serviced.
- intermittent or failing drive unit ... while it may not assist in identifying an intermittent drive unit, the drive unit test specified within the FAQ found here may identify a failure of the drive unit. Should a fault be found with the third party drive unit, then we may be able to specify a Raymarine drive unit as a replacement if provided with some details of the vessel.

[SVNeko]

Thanks, Chuck. The drive stop issue only happens intermittently, which makes diagnosis difficult. I do not think it is the drive, since the drive responds to direct power input consistently. I have had the ACU checked by Raymarine about a year ago and last week by a local Raymarine authorized tech. Both times it checked out as working properly. My question is whether it is likely that the ACU fails periodically, and if this can be checked. Also, which newer model would be helpful as a replacement.
Thanks,
Peter Malloy

[Chuck - Raymarine - Moderator]

Peter,

Unfortunately, intermittent problems can be difficult or impossible to isolate, particularly those which occur very infrequently. Autopilot course computers do not generally fail in an intermittent manner. The symptoms reported would typically be associated with insufficient power or an intermittently failing autopilot drive unit. A SPX30 would typically be replaced with an Evolution ACU-400. Please note that installation of an ACU-400 will additionally require replacement of the autopilot control head with a p70 Autopilot Control Head and replacement of the currently installed fluxgate compass with and EV-1 Sensor Core.

[SVNeko]

I have an unfortunate update on this Drive Stop issue. Believing the source of the problem to be a faulty drive pump, we replaced the pump at great cost. It has not solved the Drive Stop fault. Subsequently, we have met in our travels two other boats suffering the exact same problem with an X30. One has a Lewmar Mamba drive and the other a Raymarine hydraulic drive. So we have three X30's all with different drives and all suffering the same problem. Unfortunately, this X30 was serviced by Raymarine 1.5 years ago and a very experienced Raymarine agent in Martinique recently, neither of which found a reason for this problem. Due to its intermittent nature I believe it is very difficult to diagnose but I am now convinced it is some kind of fault with the computer.

[Chuck - Raymarine - Moderator]

Peter,

As indicated within my initial response, should the problem may result from insufficient power being supplied to the autopilot course computer. While depletion of the battery charge below the voltage level required for the autopilot to operate is the most common cause for insufficient power being supplied to the autopilot, insufficient power may also result from not having isolated the marine electronics from the vessel's other devices consuming large amounts of power. Please click here to view a FAQ addressing this subject. However, should you have verified that such isolation has been installed and the problem persists, then it would be advised that the X30 be sent to Raymarine’s Product Repair Center to be bench checked / serviced. The note accompanying the product should specify the intermittent nature of the problem, to include the frequency (time between failures) and the voltage level measured at the course computer at the time of the failure.