Washer would not drain

Simply replaced the main control board with the new part and turned the machine on to test the repair. Problem was not solved. Opened washer cabinet, providing access to the pump, drained the waasher tub manually, and disconnected the suction and discharge hoses at the pump. A handkerchief was found in the suction hose, at the pump intake/suction nozzle. Removed handkerchief, connected hydraulic lines and started washer. Washer drains as it should. Problem was the handkerchief in the pump suction. New control board solved a "second rinse" problem.