bosch dryer logixx 10 doesnt stop.

well lads any service info/ manual would be greatly appreciated. A bosch dryer landiped in the workshop today. its a 10kg dryer WTB76556gb/06. when you turn the selector switch she turns on straight away without even pressing the “start/pause” button. you have to hold the start pause button for 4sec to get it to heat as it appears its stuck in child lock but when the timer goes to zero it doesnt finish. it still tumbles around and the start pause button doesnt even stop it unless you turn the selector switch to off. any ideas. is it the ignition switch behind the door thats faulty or is it the pcb. over 400e for a new pcb