On a previous thread ( Control Pedal Issue) Pfaff 1222 sewing machine foot pedals were discussed. It was determined that the proper foot pedal used a 20K potentiometer. I also have a Pfaff 1222 but an earlier version. No one seems to know what value potentiometer is needed in the foot pedal for the machine that I have. I have some input that a 150k potentiometer is needed but no one seems to sell one or have any information about one. There is a trim pot in the electronics on the machine. Is there some way to check the pedal input to the machine electronics to determine what size potentiometer is needed? The machine regulates the motor speed by thyristor phase control.