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: 1767

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

Loading…
  • Add Photos
  • View All

Latest Activity

Robert Garrett liked Robert Garrett's profile
Sep 13
James Coolbaugh replied to Michael McDonald's discussion Integrating ST60+ instruments to eS78 Chartplotter via Seatalk Conversion Kit
"Greetings, Thia may be a bit late,but I'll try. I just installed the eS78 MFD with the Quantum (wireless) radar, which I want to use with my existing ST60 series instruments. With my old radar, they interfaced fine, but with the new…"
Sep 8
martin schulman replied to martin schulman's discussion nmea connector- C 80 chartplotter to VHF
"I can give you very little help here. After jerking around with the connection for months I finally decided to skip it. The Standard Horizon, which works beautifully despite the small screen is below and required leaving the helm to read.  I…"
Sep 4
Peter Stewart replied to martin schulman's discussion nmea connector- C 80 chartplotter to VHF
"I am purchasing a Standard Horizon gx2200 vhf with GPS and AIS. I currently have a C80 MFD. On the back of the mfd the NMEA IN/OUT connection is available. Using a RO8004 cable with the appropriate connection on one end can I join up the C80 at the…"
Sep 4
COUCHSAILORS.com updated their profile
Aug 24
COUCHSAILORS.com replied to Steve C's discussion ST60+ Tridata Not Calibrating to SOG
"When I press reset to accept the SOG which I am seeing it beeps but still shows 0.0 and doesn't transfer the SOG to the speed. Please advise."
Aug 24
Tom Arnold updated their profile
Aug 22
Donald Evans replied to Lorenzo Vanni's discussion Raychart BC420 and Evermore SA-320
"All I can say is try getting your position by using the white wire! I know Ariel Cheng, she is just a temp. She doesn't know how to distinguish one wire from another. I used to deal with Evermore and found their receivers to be poor, thin wires…"
Aug 21
M.Catarall replied to Lorenzo Vanni's discussion Raychart BC420 and Evermore SA-320
"You say Correct it is White wire: Rx, imput signal not data out but data in as shown on reply from Evermore"
Aug 21
Donald Evans replied to Lorenzo Vanni's discussion Raychart BC420 and Evermore SA-320
"Seems you still don't understand what Cheng is saying."
Aug 21
M.Catarall replied to Lorenzo Vanni's discussion Raychart BC420 and Evermore SA-320
"Evermore ( Mrs Ariel Cheng ) answered me Today: Hello Lorenzo, Red wire: VCC power (+12V) Green wire: Tx, Output signal White wire: Rx, imput signal Black wire: Ground Gray wire: Shield wire, signal ground Blue wire: Not used I did not think anyone…"
Aug 20
Donald Evans replied to Lorenzo Vanni's discussion Raychart BC420 and Evermore SA-320
"You're still wrong. Evermore white wire is not the NMEA data out. And don't call me stupid. Get your facts right before commenting."
Aug 20
M.Catarall replied to Lorenzo Vanni's discussion Raychart BC420 and Evermore SA-320
"The information was not wrong when posted. I suggest you look at the date of the post before adding stupid comments"
Aug 20
Donald Evans replied to Lorenzo Vanni's discussion Raychart BC420 and Evermore SA-320
"Hahahahaha, you're all totally wrong. Should have bought it from www.gps-galore.co.uk The guy's an expert on these."
Aug 20
Brian Kidwell updated their profile
Aug 18
Ricky Ladd replied to Joel Hjelseth's discussion Raymarine Dragonfly 7 malfunction
"I just installed my new Dragonfly 7 pro when I power it up the Dragonfly emblem comes up it then blinks goes to a blank screen with a blinking in the upper left hand corner then it goes back to the Raymarine emblem sometimes it goes to the accept…"
Aug 8

© 2017   Created by Moderator - Raymarine, US.   Powered by

Badges  |  Report an Issue  |  Terms of Service