Noise from ST50 instruments

[Roberto]

I have two autohelm ST50 analog displays, one for 360° wind direction and the other which magnifies wind direction when it comes from +-60°, usual stuff.

There is a sort of low noise coming from the displays, hard to define but like a continuous purring, humming sound coming from some rotating thing ? When there are no other noises, it can be heard up to a few metres distance, and of course my berth is inside its striking distance.
It's that sort of noise that when you try to fall asleep, either you do not notice it at all, otherwise if you hear it one time then it's impossible to get rid of it :angry:

It comes from the wind displays, as they are very near to each other I cannot say from which one in particular.

Does anyone know if there is any way of stopping it ?
Or is it possible to open the displays and have a look without having springs or needles fall away ?

 

[misterg]

... like a continuous purring, humming sound coming from some rotating thing ....

...It's that sort of noise that when you try to fall asleep, either you do not notice it at all, otherwise if you hear it one time then it's impossible to get rid of it :angry:

Perfect description - ours does that too. Took me ages to pin-point where it was coming from the first time I heard it. As you say, you don't notice it until everything else is really quiet, then once you've heard it, you can't stop noticing it.

I came to the conclusion that the pointer in the wind instrument must be driven by a stepper motor, and the noise was just the motor doing it's stuff.

I wouldn't have thought that there was any benefit in opening the instrument up, unless somebody knows otherwise.

You need to turn the instruments off when you go to sleep

Andy

 

[Roberto]

You need to turn the instruments off when you go to sleep

Andy

thanks Andy, good to know I am not alone



Yes in the end I turn everything off when I can, but for example when at anchor with a depth alarm, or just to have a wind speed indication at a glance (I have an internal repeater which is visible from my berth) it would be nice to have the instruments on without all the accompanying noise...

 

[westernman]

In my case it is the rudder angle indicator which does that. Seems to start at some random time after a few hours of use.
And it is very annoying.

Sometimes it stops when I press a couple of the buttons at bottom of the display at once. No idea what those buttons are meant to do - they don't seem to do anything useful.

 

[Elemental]

There is a sort of low noise coming from the displays, hard to define but like a continuous purring, humming sound coming from some rotating thing ? When there are no other noises, it can be heard up to a few metres distance, and of course my berth is inside its striking distance.
It's that sort of noise that when you try to fall asleep, either you do not notice it at all, otherwise if you hear it one time then it's impossible to get rid of it :angry:

Yep. Mine does the same too. Interestingly it's only started doing it this season. It was totally silent last season. I also fancy I can see a very slight 'tremble' in the direction indicator which seems to match the noise. Doesn't keep me awake at night though.

Mark