Velleman doesnt mention it in there manual but i will do it here. When assembling the K8400 or you need to move the head with your hands. Disconnect all wires attached to the 3d main printerboard.
The steppermotors generate electricity when you move them by hand, you need some time of tinkering after assembling(and afterwards) to get the great results.
I don’t get it? Could you explain a bit more?