[CA] [CA11] SmartPilot has failed

[lord phi]

My Raymarine auto pilot has just failed and I need some help to diagnose what is wrong.

The installation comprises
1. SmartPilot Computer – S3
2. SmartPilot Controller – ST7001
3. Fluxgate compass
4. Rudder position sensor
5. Drive unit

The fault shows thus: on Standby the rudder position (shown on the Controller) shows the rudder to be on full left lock, irrespective of the actual rudder position. When Auto is selected there is some movement of the rudder however an alarm sounds and “No Rudder” message is displayed.

My (low skill) testing shows:
• All Computer fuses are good.
• With the Motor terminal wires disconnected the Computer ‘Motor’ terminals deliver: 0 volts on Standby, 4.76 volts rising to 11.86 volts with Auto engaged and a turn of 30 degrees selected, this returns to 0 volts if an additional 10 degrees are added.
• The Clutch terminals of the Computer carry 11.86 volts when Auto is selected.
• Voltage is present at each of the Fluxgate compass connections (too difficult to make out each of the individual voltages).
• The Rudder position sensor wiring (at the sensor) carry a voltage, which changes as the sensor angle is altered (manually).
• The Drive unit is an unknown (to me).

Can you suggest what is wrong, any further tests I should try and what I should do to rectify the situation