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7 Fault finding
7.1 General
Before you contact your Nexus dealer and to assist your dealer to give you a better service,
please check the following points and make a list of:
•
All connected instrument and transducers, including their software versions.
•
Nexus Network ID numbers for each instrument (displayed at power up).
In most cases, the reason for faults in electronic equipment is poor installation. Therefore,
always first check that:
•
Installation and connection is made per instructions for instruments and transducers.
•
Screw terminals are carefully tightened.
•
No corrosion on any connection points.
•
No loose ends in the wires, causing short cuts to adjacent wires.
•
Cables for damage and that none are squeezed or worn.
•
Battery voltage is sufficient, should be at least 11 V DC.
•
The fuse is not blown and that the circuit-breaker has not opened.
•
The fuse is of the right type.
•
Two instruments do not have the same ID number.
7.2 Symptom - Cause - Action
In the table below, causes marked [ * ] are more likely to occur during installation or when
rewiring has taken place.
Symptom
Cause
Action
Autopilot turns off
* Voltage below mini-
mum.
Make sure 12/24 V is applied to battery
terminals at Servo Unit.
Autopilot does not turn
on
* Voltage not applied.
Make sure 12/24 V is applied to battery
terminals at Servo Unit.
* Voltage polarity is
reversed.
Make sure + and - is applied to correct
terminals
* Boats safety switch is
open.
Close the safety switch.
* Fuse burned out.
Check and replace fuse as necessary, lo-
cated in the Servo Unit.
Autopilot turns on, but
the pumpset does not
run
Slow blow (high current)
fuse in Servo Unit is
blown.
Replace fuse. If fuse regularly blows,
check for excessive rudder load or me-
chanical defects in steering system
Pumpset drive section
in Servo Unit may have
failed to open.
Replace transistors, integrated circuits or
entire circuit board.
Pumpset motor turns but the
rudder does not move
Broken or loose motor cou-
pling.
Replace or tighten coupling as necessary.
Pumpset contamination
Clean or replace pumpset
FAULT FINDING
