Main drive will not start

I have an L8-55 beckman that the other day decided it will no longer spin.

You set up a run and hit auto run and the LED flashes above the auto run button and then shuts down after 15 seconds. None of diagnostic messages light up after this. The vacuum will start and pull down to level but the rotor will never start spinning.

However if you turn on the slow accelertion feature the speed diagnostic light will then flash after pressing the auto run but there is still no spinning.

Any suggestions on things to check?