Just an update on my quest for a spare drive motor for my AH3000.
Although the raymarine site replied that parts are available for these
units, our local service depo found what appears to be a new complete
drive unit on their shelves. I bought it for $500 CAN. As I said
previously I run the old drive unit with the new 4000+ head and
fluxgate. They at first said that the only difference in the old and new
motors is the gear ( I expect that the old gear can be fitted to the new
motor)They now say that there is an issue with the pin that locates the
motor. This can be relocated by redrilling.