[C320-list] ST 4000 autohelm problem

[Bruce Heyman]

The stepper motor that they use for the Auto helm draws a lot of current.
Depending on the quality of your connections and the dimension of your wires
this will cause a voltage drop.  Once you get down to about 10 volts most
GPS I've seen will reset.  Same with the instruments.  I'm pretty sure that
the manual recommends an isolated 12v feed for the motor.
Put a DVM on the 12v feeding the GPS and watch what happens when you switch
on the auto helm and the stepper motor turns on.
Bruce
Somerset #671 SoCal

-----Original Message-----
From: c320-list-bounces at lists.catalina320.com
[mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Gene Musante
Sent: Saturday, May 17, 2008 4:05 AM
To: Catalina, 320 intl
Subject: [C320-list] ST 4000 autohelm problem

Hi,
 
I mounted up my boat's wheel for the season and connected the servo motor to
it's electrical connection on the pedistal.  When I switched the power on,
my power kept switching off and on at about a 1 second frequency on the
autohelm display and my tri-data display.  My GPS, which is connected to the
same power feed was having the same problem.  I disconnected the servo motor
electrical connector, and the power came on and stayed on.
 
My hunch is that the servo motor may be defective, but it was working fine
in the fall before I dismounted the wheel, which I store inside the boat.  I
am going to dismount the wheel and re-assemble the whole works to see if
this could have been caused by a mechanical problem.  I forgot that the
wheel lock was on when I first switched on the power which may have caused
the problem initially.
 
Has anybody seen this problem on their boat?Gene Musante  617-755-0680
gmusante at msn.comAFFINITY Hull #68