You can usually tell by the sound. Does it spin frely one way and try to go back but locks up with a thud. If not then can you only hear it spin freely one way followed by silence then spin again? The first sound would tell me the clutch is engaged usually because brake is not locked into gearbox. If you lie the machine down and take hold of pulley, it should turn freely both ways. The 2nd sound would tell me the motor is only turning on for one direction which could be a faulty timer. Probably best to get someone out to fix.
Lincoln Appliance NZ, May 2016
