Richard10002
Well-Known Member
Skip to THE CRUX OF THE PROBLEM below if not bothered about the linear drive, and my sore head!
Some may be familiar with the problems I have had with the Autohelm Linear Drive Unit part of my autopilot.
Anyway... after some new parts, (gears), lots of help here, some great help, and an exploded diagram, from Raymarine UK, many dismantlings and refittings, I think I have got rid of the "stiction" and it seems to run freely from hard over to hard over, both on Auto and on Standby.
I had put 4 planetary gears on upside down.... the raised part of the gear should face the belt drive gear... which will make sense if you ever take one apart.
Anyway, as these bits are always in the most awkward positions... whilst fitting the drive for hopefully the last time, I was kneeling on the stern bunk, leaning into the steering gear space, with this heavy lump of drive in one hand, and 2 bolts in the other, when I overbalanced forwards and, despite putting my hand out to break my fall, I only came to rest when my head hit the rather sharp and solid nut thing which sticks out of the top of the rudder post. I remained in this position for some seconds, whilst I summoned up the strength in one arm, to push 15 stone of bodyweight back onto the bunk. I wont repeat what I said....
THE CRUX OF THE NEW PROBLEM>>>
Anyway, it was only then that I realised that the thing which I had grabbed to stop my fall was the delicate arm of the Rudder Reference Transducer, whose ball joint had come off the rudder arm and, as it seems to have some kind of spring inside it, seems to have unravelled through several 360 degrees.
I wound it back round to what seemed correct, put the ball joint back on the rudder arm and fitted the linear drive, (which was why I was there in the 1st place).
Turned on the autopilot and instruments, tested the autopilot, which now seems to work fine, but.....
The rudder angle shows hard over to starboard, no matter where the rudder is. Tried winding and unwinding the transducer through a few 360 degrees to no effect.
Checked the resistance at the computer end of the transducer wire, and get 5kohms at all angles of the rudder... Raymarine say it should be 5kohms at hard over, and 2.5kohms at midships.
some posts here seem to suggest that it will show hardover if there is no power getting to it, which is possible. Raymarine suggest getting a new one if disconnecting and reconnection doesnt fix it, (well they would wouldnt they).
I am tempted to snip the wire at the transducer end, and take it to bits to see if the wires have come loose... it's only a potentiometer after all, (whatever that is <g>), but it's definitely got a spring in it, and I may screw things up completely.
Anyone with an intimate knowledge of these things? Any suggestions and info welcomed
Otherwise it's another £200 or so for a new one.
Many Thanks
Richard
Some may be familiar with the problems I have had with the Autohelm Linear Drive Unit part of my autopilot.
Anyway... after some new parts, (gears), lots of help here, some great help, and an exploded diagram, from Raymarine UK, many dismantlings and refittings, I think I have got rid of the "stiction" and it seems to run freely from hard over to hard over, both on Auto and on Standby.
I had put 4 planetary gears on upside down.... the raised part of the gear should face the belt drive gear... which will make sense if you ever take one apart.
Anyway, as these bits are always in the most awkward positions... whilst fitting the drive for hopefully the last time, I was kneeling on the stern bunk, leaning into the steering gear space, with this heavy lump of drive in one hand, and 2 bolts in the other, when I overbalanced forwards and, despite putting my hand out to break my fall, I only came to rest when my head hit the rather sharp and solid nut thing which sticks out of the top of the rudder post. I remained in this position for some seconds, whilst I summoned up the strength in one arm, to push 15 stone of bodyweight back onto the bunk. I wont repeat what I said....
THE CRUX OF THE NEW PROBLEM>>>
Anyway, it was only then that I realised that the thing which I had grabbed to stop my fall was the delicate arm of the Rudder Reference Transducer, whose ball joint had come off the rudder arm and, as it seems to have some kind of spring inside it, seems to have unravelled through several 360 degrees.
I wound it back round to what seemed correct, put the ball joint back on the rudder arm and fitted the linear drive, (which was why I was there in the 1st place).
Turned on the autopilot and instruments, tested the autopilot, which now seems to work fine, but.....
The rudder angle shows hard over to starboard, no matter where the rudder is. Tried winding and unwinding the transducer through a few 360 degrees to no effect.
Checked the resistance at the computer end of the transducer wire, and get 5kohms at all angles of the rudder... Raymarine say it should be 5kohms at hard over, and 2.5kohms at midships.
some posts here seem to suggest that it will show hardover if there is no power getting to it, which is possible. Raymarine suggest getting a new one if disconnecting and reconnection doesnt fix it, (well they would wouldnt they).
I am tempted to snip the wire at the transducer end, and take it to bits to see if the wires have come loose... it's only a potentiometer after all, (whatever that is <g>), but it's definitely got a spring in it, and I may screw things up completely.
Anyone with an intimate knowledge of these things? Any suggestions and info welcomed
Otherwise it's another £200 or so for a new one.
Many Thanks
Richard
