LG F8068QDP direct drive washing machine - drum not spinning properly

[topperdoggle]

I hope this video tells the story: https://www.youtube.com/watch?v=O8L5ySXen68

It started last weekend, I put the washing on, came back hours later and it was stuck, water in the machine. Moved the machine out to make sure the drain hose wasn't blocked (it wasn't), left the clothes to dry in the sun, then tried again this weekend and same thing. This time I caught it before it gave up. As you see in the video, the drum wants to spin but can't (maybe a couple of cm in either direction).

The tub does spin freely by hand.

I've searched the web endlessly but I'm no closer to a solution. It can't be carbon brushes because this type of motor (direct drive) uses an inverter, not brushes. It can't be the drive belt because there isn't one. I can't find a service manual online.

Where do I go from here? I'd really rather not have to throw it out.