1 Check that the light comes on, if not check the fuse in the plug.
2 Make sure the power cable is correctly plugged into the machine.
3 If the machine is plugged into an extension, check the extension or plug the machine directly into a wall socket.
4 Some Overlockers have a buit in saftey switch on the looper cover, check that the looper cover is correctly closed which will engage the switch.
5 Manually turn the handwheel to see if the machine moves freely, the machine maybe jammed and require a service or repair.