Hello folks,
Had one in today, where on pressing the go button, the Green Led would flash and the motor just twitch. Thought duff Lithium battery, so checked it with a decent load, and battery wasn't duff.
On to YouTube, where seems three ancillary battery connectors (as it's Lithium and liable to explode) were regarded suspect and needed a clean-up - did that - still no go.
Another chap on the Tube suggested dodgy soldering to the three feedback connectors were suspect.
Motor plastic backplate moulding seems secured by a single screw, but after removing, suspect it's glued on, as couldn't remove it without causing considerable damage - So didn't bother.
Seems very Dyson - Technology 'Triffic - construction - Total Crap - Chris.