[CA] [CA11] Autopilot loosing calibration settings

[SetFree]

Our new-to-us boat has a ST7001 control head interfaced to a S3G AST course computer. Each time I start up the instruments, I notice that the autopilot heading does not match the GPS heading - it's off by 15 degrees or so.

I have gone through the Seatrial Heading match calibration procedure which corrects the problem as long as I don't turn the system off. However, after the autopilot has been off, the heading is once again incorrect. I'm concerned if other calibration settings are being lost as well.

Can you let me know what can be done to preserve these settings? Thank you

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum SetFree,

The reported issue may be indicative of a problem with the S3G's gyro or with the circuitry of the S3G. This may be verified by unplugging the gyro's cable from the S3G's circuit board. Please click here to view a FAQ addressing this subject. Re-calibrate and align the S3G's compass, tie the boat to a dock, note the heading, shut the system down for approximately 10 minutes, unplug the gyro's cable from the S3G's circuit board, and then power up the autopilot. If the heading changed, then the problem is rooted in the circuit board, necessitating that the course computer be replaced as Raymarine can no longer service the S1/S1G/S2/S2G/S3/S3G autopilots. If the heading did not change, then the problem is rooted in the gyro, necessitating that it remain unplugged. In the case of the latter, the autopilot will function as a S3 rather than a S3G autopilot. Replacement gyros for S1G/S2G/S3G autopilots are no longer available.

If seeking a currently manufactured autopilot to replace a S3G, then a T70161 Evolution EV-400 Sail or T70162 Evolution EV400 Power would be recommended. The currently installed rudder referenced transducer and drive unit may be retained for use with the Evolution autopilots specified.