Raymarine ST70+ Operating Manual page 69

Chapter 4: Maintenance & Troubleshooting
Symptom
Boat turns slowly and takes a
long time to come onto course,
under autopilot control
Boat overshoots when turning
onto a new course under
autopilot control
The autopilot 'hunts' when
trying to position the rudder
If it appears that ST70+ is not operating satisfactorily, check the symptoms below to
determine how to resolve the problem:
• Nothing on the display screen – refer to Figure 4-1, Troubleshooting chart 1 .
• Data missing from the display screen – refer to Figure 4-2, Troubleshooting
chart 2 .
• Data on the display screen is garbled – refer to Figure 4-3, Troubleshooting
chart 3 .
• Specific data types are missing or incorrect:
• Check the relevant Transducer and Pod, including the connections between
them and to the system.
• If speed readings are missing or obviously wrong, the speed transducer pad-
dle wheel could be fouled and need cleaning.
Possible cause/remedy
Rudder gain too low. Complete AutoLearn or increase
gain setting (see Chapter 3: Setup Information).
Rudder gain too high. Complete AutoLearn or decrease
gain setting (see Chapter 3: Setup Information).
Increase the rudder damping one level at a time until the
autopilot stops hunting, and always use the lowest
acceptable value. (see Chapter 3: Setup Informa-
tion).
61