DriveStop message

[DaveW]

Hello Chuck,
I am getting a DriveStop fault fairly regularly.

6000+ Autopilot Control
400G course computer
Type 2 linear drive

The "DriveStop" occurs after the autopilot has been in use for a while ( 20-30 mins). Voltage output to the linear drive seems normal, but just prior to the Drive Stop message the voltage drops. Voltage was checked at terminals on computer and at drive unit three feet away. No resistance was noted in the wires between the computer and the drive unit. Upon setting the controller in autopilot mode, ten degree adjustments were made, port and starboard, and voltages at the drive output varied from 6.8vdc to 7.5vdc during course corrections. This remained constant until the second to last course correction, when voltage dropped to 2.8vdc and finally 0vdc after which the "Drive Stop" error message appeared. Input voltage at the autopilot computer remained at 12.8vdc throughout the test. The Drive stop seems to occur as a result of the voltage drop, which leads me to believe it may be the computer. After going to STbY for a bit of time I can re-engage the autopilot. It will work for a while, then Drivestop returns. That led me to think there may be an internal issue. Am I on the right track? Or is there something else to be aware of?

At the control panel, the rudder ref position was continually displayed and correct.

As the 400G computer is no longer supported by Raymarine, I would likely have to replace with a similar or compatable model. Would the S3G or other newer model be suitable?

Regards,
Dave