HD Digital open array not rotating

[zelatore]

I am troubleshooting a 4KW HD Digital 4' open array. Initially the VCM would not come out of sleep mode. The core was sent to Raymarine, a minor issue noted and repaired, and it was re-installed. The problem persisted but intermittently. The cable was then replaced. The unit is now seen on the network and can be activated, however the scanner rotates only a couple turns before stopping and displaying a message of no rotation. If turned by hand, the scanner turns freely and there is no visible issue with the belts or drive assembly.

As an FYI, the boat is plugged into shore power with chargers running and the batteries are fully charged.