25
Symptom
Cause
Action
Blinking [Low Bat] on bottom
line of display
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).
Turn Autopilot off and charge batteries, or correct
voltage loss. When proper voltage restores, restart
Autopilot.
Poor wiring connection.
Check for voltage drop and repair.
Power wiring is undersized.
Replace wiring with correct diameter wire.
When Autopilot engaged,
rudder goes harddover.
APC routine not performed.
Perform APC routine.
Power transistors in Servo
Unit may be shorted.
Replace transistors or entire circuit board.
Rudder transmitter linkage
disconnected.
Re-connect and align as per installation instruc-
tions.
Rudder transmitter wiring
shorted or open circuit.
Check and repair wiring as necessary.
Autopilot wanders on some
headings
Magnetic interference is pre-
sent. The worst steering is
usually on northerly headings
in the northern hemisphere
and southerly headings in
the southern hemisphere.
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.
Autopilot wanders on all
headings
Severe magnetic interfer-
ence.
Choose another compass location.
Air in hydraulics.
Fill and purge the steering system.
Slack in the steering system.
Repair any loose or worn parts.
Rudder transmitter potenti-
ometer is "noisy" or inter-
mittent.
Replace rudder potentiometer.
Compass damaged; inter-
mittent wiring connection
Repair any loose or worn parts; recheck and con-
nect wiring.
Slow wander means rudder
control is set too low (under-
steering).
Increase Autopilot setting [P1] [RUD]
Fast wander means rudder
control is set too high (over-
steering).
Decrease Autopilot setting [P1] [RUD]
Autopilot wanders on all
headings.
Excess rudder load.
Reduce rudder friction, increase steering cylinder
size, increase power of the pumpset.
Rudder movement is erratic
Air in system.
Check for leaks and bleed the system.
Rudder angle indicator is
displaying erratic values.
Rudder transmitter is defec-
tive (noisy).
Replace rudder transmitter or potentiometer within.
Check for loose or broken
wires in terminal strips.
Reconnect tightly.
Check for broken wires in
cables.
If wiggling of cable where it flexes causes rudder
activity, replace cable.
Boat overshoots on large
course changes.
Rudder control set too high.
Decrease Autopilot setting [P1] [RUD]
Counter rudder set too low.
Increase Autopilot setting [P3] [CRD]
Cause
Action
FAULT FINDING
