Nexus AUTOPILOT Installation And Operation Manual page 26

Symptom
Blinking [Low Bat] on bottom
line of display
When Autopilot engaged,
rudder goes harddover.
Autopilot wanders on some
headings
Autopilot wanders on all
headings
Autopilot wanders on all
headings.
Rudder movement is erratic
Rudder angle indicator is
displaying erratic values.
Boat overshoots on large
course changes.
FAULT FINDING
Cause
Low battery voltage. Auto-
matic shut-off in case of
voltage lower than 10.5 V (12
V battery) and 21.5 V (24 V
battery).
Poor wiring connection.
Power wiring is undersized.
APC routine not performed.
Power transistors in Servo
Unit may be shorted.
Rudder transmitter linkage
disconnected.
Rudder transmitter wiring
shorted or open circuit.
Magnetic interference is pre-
sent. The worst steering is
usually on northerly headings
in the northern hemisphere
and southerly headings in
the southern hemisphere.
Severe magnetic interfer-
ence.
Air in hydraulics.
Slack in the steering system. Repair any loose or worn parts.
Rudder transmitter potenti-
ometer is "noisy" or inter-
mittent.
Compass damaged; inter-
mittent wiring connection
Slow wander means rudder
control is set too low (under-
steering).
Fast wander means rudder
control is set too high (over-
steering).
Excess rudder load.
Air in system.
Rudder transmitter is defec-
tive (noisy).
Check for loose or broken
wires in terminal strips.
Check for broken wires in
cables.
Rudder control set too high.
Counter rudder set too low.
Cause
Action
Turn Autopilot off and charge batteries, or correct
voltage loss. When proper voltage restores, restart
Autopilot.
Check for voltage drop and repair.
Replace wiring with correct diameter wire.
Perform APC routine.
Replace transistors or entire circuit board.
Re-connect and align as per installation instruc-
tions.
Check and repair wiring as necessary.
Perform Auto-Deviation-Clear [CLR] and Auto-
Deviation [DEV] again, or try another compass lo-
cation. Investigate for magnetic disturbances
around compass, e.g. masses of steel, motors,
loudspeakers etc.
Choose another compass location.
Fill and purge the steering system.
Replace rudder potentiometer.
Repair any loose or worn parts; recheck and con-
nect wiring.
Increase Autopilot setting [P1] [RUD]
Decrease Autopilot setting [P1] [RUD]
Reduce rudder friction, increase steering cylinder
size, increase power of the pumpset.
Check for leaks and bleed the system.
Replace rudder transmitter or potentiometer within.
Reconnect tightly.
If wiggling of cable where it flexes causes rudder
activity, replace cable.
Decrease Autopilot setting [P1] [RUD]
Increase Autopilot setting [P3] [CRD]
Action
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