Old Washer Spin Enable Switches: A mercury type spin-stop lid or door safety switch was used on most automatic washer appliance models until very recently. This device is mounted by a bracket to the lid hinge. This position ensures proper operation of the appliance, which depends on mercury within the capsule to make or break the contact. When the appliance owner raises the lid during spin, the mercury in the switch capsule runs away from the switch contacts, and the timer circuit to the spin solenoid is broken.
During ‘on’ time of spin direction timer IC2, the output of negative- edge triggerd JK flip-flop at pin 2 goes low to energise relay RL2 and washing machine motor rotates in one direction. During the off time of IC2, the output of N1 goes high again to de-energise relay RL1, which cuts off the mains supply to RL2 and the monitor stop rotating. Floating point trouble may occur at trigger pin 2 of IC1. Resister R8 over comes this problem by holding pin 2 high.