ST7002 Autopilot
While we were in the Amazon Delta last month our ST7002 autopilot quit working. The unit made a loud grating noise - it sounded like spinning gears which were not fully engaged. The fly in the ointment is that the unit started out life as an Autohelm 7000. We have replaced the control head, but the computer and the type 2 long linear drive unit are the original Autohelm components. We think that the unit was manufactured around 1991 - this is based on the motor label which indicates DATE 2/90.

I dismounted and opened up the linear drive unit. The inside of the linear drive unit had a large amount of black dust - it appeared to be brush carbon, but could have come from the black plastic gears. The drive belt (300 3M 12 469D) had some wear, but it appeared to be in serviceable condition. I disassembled and inspected the components. I connected a source of 12VDC to the motor - it ran fast and smooth. The resistance between the leads of the motor is .6 ohms (measured with a Fluke Model 23 Series II digital multimeterI). I connected the 12VDC source to the clutch coil and it had a strong magnetic field. The resistance of the clutch coil is 27.3 ohms. The clutch coil seems free to slide axially on its mounting pin. Both the small motor drive gear, and the large belt driven gear on the drive shaft seem to be serviceable. When I pull the tiller arm in and out, the planetary gear unit rotates freely. However, there is quite a radial wobble in the 4 planetary gears, which allows the clutch top / planetary gear housing to have a radial wobble.

I removed the circlip on the shaft end and pulled the steel clutch plate / plastic drive gear assembly. Both the shaft bushing and the plastic ring gear teeth on the clutch appear to be serviceable. I removed the roll pin securing the brass planetary gear base to the output shaft. The wobble in the planetary gears is as a result of excessive wear of the small drive gear which engages the 4 pinion gears. The planetary gears do not seem to be excessively worn.

I called the Raymarine Technical Department and spoke with Mark - he was quite helpful. He told me that the problem was that parts are not available for units built before 1989. The motor-side of the baseplate has a three box label with the following numbers: (upper two boxes) 2029 and 12V, (the lower box) 400004. There is a label on the FRACMO motor (serial 3666/366) with "DATE 2/90" - which indicates that if the motor was manufactured in February 1990, then this unit was built sometime after that date. Attached are 10 photos for ID purposes.

Mark told me to set up an account on this forum and post the information I had so that the folks in England can try to establish the date of manufacture for this unit. Then we can order the correct replacement parts. It is my understanding that there is a bronze gear replacement kit to upgrade the plastic gears. I would like to not only replace the broken components, but anything else you think we need to do. We are headed for the Panama Canal, and it is a long way across the South Pacific. I started out my career in the US Navy as an electronics technician, so with some guidance and the needed repair parts, we ought to be able to repair the unit.
Warm regards,
Tom Service
S/V Tiger Lilly
Spanish Waters, Curacao

Views: 1875

Attachments:

Reply to This

Replies to This Discussion

I apologize for the delay, wanted to speak with our linear drive technician about your issue.

He explained that you will need planetary gear kit N021, this will come with the brass gears. He also suggested due to the age of the motor, he would recommend a new motor, and keep as a spare in case you get into any issues in the future, motor part number N002.

Are the part numbers the same for a type 1 linear drive?

Rodney,
I am the wrong guy to answer your question. I am just another boat owner who needed information from Raymarine.
You need to open a separate topic, and wait for the Raymarine technical wizzard (Underway - Raymarine, US) to answer you. It took them a couple of days to get back to me.
If you do take the same brass gear kit (N021), and you are in the Caribbean, Budget Marine carries these parts.
Tom Service
S/V Tiger Lilly
Spanish Waters, Curacao, N.A.



Rodney Kidd said:

Are the part numbers the same for a type 1 linear drive?

The brass gear kit is the same, N021.  The motor part number is different, for the Type 1 the part number is N001.

Reply to Discussion

RSS

Events

Videos

  • Add Videos
  • View All

Photos

  • Add Photos
  • View All

Latest Activity

Eric West updated their profile
Tuesday
Mark Chapman updated their profile
Jan 12
aaron sherman updated their profile
Jan 10
Craig T. Olsen updated their profile
Dec 31, 2017
David Lane replied to Tiago Menezes's discussion Night mode
"Good day and happy new year to this forum group.   Question: When can we expect Raymarine to ad a night color palette to its line of MFDs?  It’s been talked about in this forum for at least 3 years.   I am 100% satisfied with…"
Dec 31, 2017
Bob Atkins replied to Bob Atkins's discussion Current C-MAP NT+ and NT chart chips do NOT work properly on RL70C
"Hi Thomas, Please read the moderator's instructions on April 8, 2013 and my posting on October 31, 2013 on page 1 of this discussion. The issue has to do with the Plotter Mode setting. The Plotter Mode must be OFF for all…"
Dec 30, 2017
THOMAS A RICH replied to Bob Atkins's discussion Current C-MAP NT+ and NT chart chips do NOT work properly on RL70C
"Good Morning, I also have a Rl80 with the old chip and has worked perfect without any updates except last month it performed exactly as you described.  The maps I have always used now say no Data.  I was going to buy a new chip, but not…"
Dec 30, 2017
Northlightinvest replied to Ben Campbell's discussion Wheelpilot Broken Part
"Dear raymarine team! Please, give information, that where can I order this part from Hungary. 3001-984-B Thanks!"
Dec 27, 2017
Russ Colombo left a comment for lee christiansen
"Lee: Guilty as charged, now gleeful denizen of Marco Island and still sailing.  How good of you to contact, and what news??? "
Dec 14, 2017
Russ Colombo and lee christiansen are now friends
Dec 14, 2017
Russ Colombo updated their profile
Dec 13, 2017
Herve Pugin replied to cliff mesirov's discussion Mirroring via VGA to HD TV
"I have a trouble with a Gs95 HDMI output, Is the format the same: 720P ?"
Dec 11, 2017
Matthew Peacock replied to Philippe Jean Figueroa's discussion System builder and Visio icons
"Bump.  Still not resolved."
Dec 2, 2017
Bill Sincox updated their profile
Dec 1, 2017
David Jovanovic commented on Ross Smelley's blog post ECI-100 to Volvo Penta EDC1
"I hawe the same question ! Regards"
Nov 24, 2017
Sam updated their profile
Nov 20, 2017

© 2018   Created by Moderator - Raymarine, US.   Powered by

Badges  |  Report an Issue  |  Terms of Service