The contact is nothing more than a brass washer sliding over PCB tracks, so I imagine with lack of use it would tarnish and cease to conduct. I think somebody has suggested the grease you use on electrical contacts, but I haven't tried this.
It's also important to position the motor accurately, otherwise the washer can miss the PCB tracks entirely or even short them together. If the position is slightly out it can be corrected by bending the actuating rod.
It's also important to position the motor accurately, otherwise the washer can miss the PCB tracks entirely or even short them together. If the position is slightly out it can be corrected by bending the actuating rod.