Autohelm course computer type 300

[DJBLUELADY]

Hello
I have mounted on my 38` semi displacement traweler old Autohelm auto pilot with ST7000 head and type 300 course computer (12V). For me uknown reason display start to showing wrong course, actually always 143 degree =/- 5-15 degree. I try to rotate flux gate compass but on display appear always same course. Even I mounted new flux gate compass but no change. Obviosely problem is in input of course computer. All other functions of course computer work. Does anybody have schematis diagram of this type of course computer or sombody hade same fault? Any help is welcome.
Thanks in advance Dusko

[noelex 77]

Welcome to the forum Dusko
My only suggestion would be to use an NMEA fluxgate compass instead. If the other NMEA inputs are working this will probably restore your heading data.

Also double check all connections Make sure there is no new magnetic field near where the fluxgate compasses were mounted. its amazing the things with magnets in them these days (like glasses cases)

[DJBLUELADY]

Thanks Noelex77
But Autohelm course computer type 300 is old design and from standard interfaces have only Sea Talk but not NMEA. Connection for flux gate compass is compass proprietery inerface.
BR Dusko

[noelex 77]

Originally Posted by DJBLUELADY

Thanks Noelex77
But Autohelm course computer type 300 is old design and from standard interfaces have only Sea Talk but not NMEA. Connection for flux gate compass is compass proprietery inerface.
BR Dusko

The 300 computer on its own will only accept seatalk, but a lot of Raymarine equipment (like chartplotters) will accept a NMEA input and output this on the seatalk bus. You will need a NMEA compass (not raymarine )
The other option is a seatalk multiplexer to input NMEA data to the 300

One serious problem with the 300 computer is that its not compatible with the current controllers. If you cannot fix it or get one second hand (they are expensive second hand because of this problem) you will need a new 6002 or 8002 control panel, so its worth exploring all avenues to fix it.

[John A]

Did all the components, come from the same box? When you mention "old design" it may not be compatable with the drive unit or control unit.
Is the computer a Autohelm and the ST7000 a Raymarine?

[DJBLUELADY]

Type 300 have Sea Talk , but actually I did not thinking in that way (you mentioned NMEA , but 300 they do not have). I will research to solve problem in suggested way but if you have some link for flux gate compass (SEA TALK or NMEA, I have C140W plotter) would be welcome. BR

[DJBLUELADY]

Dea John
Whne I said old design it is year 1999. (My god how old desogn I am :-) ). Boat was with already installed autopilot with controller ST7000, pump type 1 and course computer type 300. It work one year and in my opinion w/o any particular reason on ST7000 appear wrong heading.I take flux gate compass in my hand and turn them for 90 degree on display show only couple of degree difference, practiacly keep steady course of 143 degree -/ 10 degree. In same time nothing new not placed near compass so there is no any outside rason for this mistake. It is same when I replace with new flux gate compass.

[noelex 77]

Originally Posted by DJBLUELADY

Type 300 have Sea Talk , but actually I did not thinking in that way (you mentioned NMEA , but 300 they do not have). I will research to solve problem in suggested way but if you have some link for flux gate compass (SEA TALK or NMEA, I have C140W plotter) would be welcome. BR

If you connect something like this
Buy NASA NMEA Compass Sensor Fluxgate Compass at Marine Megastore Chandlery 15% off orders over £300!*

(There are also gyro compasses if you want better performance.)

to your C140 via NMEA it should send the compass data to the autopilot via the seatalk connection.

It would be wise to try this set up first depending on the fault in the 300 it still may not work. If you can fix the 300 or get one second hand for a reasonable price that would be a guaranteed solution.

[DJBLUELADY]

Reading you reply I had to lough for my stupidity. But first must have you introduction. Last year I bought my boat in Guernsey. Considering Existing Lorenz (not Lowrance) chart plotter could not use new CMAP charts and in old version was not exist willing route, by intenet I engage one man company in Guernsey to install me new chart plotter (he insist on Raymarine chart plotter becuase Navionics charts are more advance , according to their explanation then CMAP). Minded Auto pilot was Autohelm I thought ti si OK. He install me but in same time inform me that :
First, rudder ref is gone, I approve hem, to replace
Second, ftre first case that course computer is gone and new board coast app 570 pounds. I aprove them this repair too.
So when good heading cancelled I had in my mind cannot be any problem with course computer becuase he is new. So I di not test compass boving them right or left already I purchased from UK new one which coast me 90 pounds + shipping. Today when I open computer and found date 22.11.1999. and in almost same time saw your link with cheaper NMEA compass also in UK I have to loghed how mu stupid can be huge :-). I thin I beleive people to much. No matter thanks for your valuable advices. Already I found one used 300 on this forum but think will be and this NMEA compass for increasing my personal knowladge.
BR
Dusko

[DJBLUELADY]

Dear Noelex
I must apologize, there is NMEA port on 300 course computer. I check input on MB and found fluxgate compass goes on IC 74HC501D which is 8 channel multiplexer/demultiplexer and I cannot test them in static regime so I will assemble computer test them in boat and if nothing goes wrong purchase NMEA compass sensor. If found some appropriate price for second hand computer purchased them like spare too. Thanks for help

[Scorpio2]

Hi

I have a Autohelm 7000 running through a Type 300 course computer. I dismounted it to do some work, and when I turned it back on there is no heading displayed on the control unit.

The Autohelm fluxgate seems to be wired in correctly

Has anybody else had this problem where the heading is not displayed?

[DJBLUELADY]

HI
communication with head is by Sea Talk. Most probably you need to check did you wire again properly, there is no reason to do not work. If you have Tridata or echo-sounder or wind meter they also function via Sea Talk and if they work then only wiring is problem.
regards
Dusko

[ReneJK]

service manual , like this ?

tried to add an attachement , but wont work :-(

[marinaman]

Have you all contacted technical at Raymarine and asked their advice, hopefully they will not tell you to just dump your equipment. Since Flir bought the company things have changed. Not sure how much. not overly impressed by the wheel pilots.

[transmitterdan]

Raymarine have an excellent support group here: http://raymarine.ning.com add /m for mobile devices.