Step motor rattering very bad

Hey guys
My k8400 is doing strange noises ;(
Twhats false?
he X-Axis motor is rattering and the voltage of the driver is 15v
Thanks for your answers

In this thread there is a link to a video showing maybe similar noise problem as with your printer:
viewtopic.php?f=58&t=13911
Please see the reply for possible solution.

For more info please see also:
viewtopic.php?f=62&t=17386
viewtopic.php?f=58&t=13699