Have a Bosch WAE24363GB/05 which has the error F21. Have replaced worn carbon brushes but can not got rid of the F21. Have tried the procedure where you turn the knob to off then round to 6’o’clock, then holding spin button whilst turning knob to 7’o’clock then to off again but no luck. The buttons are the ones you don’t really push but sense heat from fingers [I assume].Apart from the flashing F21 machine seams dead. Any ideas gratefuully received.