Thanks John. That leads me to 2 more, and hopefully my last 2 questions :
Does the yellow wire or the white wire go to the positive side of the motor?
Finally, I've seen info from MTH saying the fan is to run counter clockwise on most locos. How do I know which locos go in which direction?
I can't believe I'm actually attempting repairs like this, but thanks to everyone on this forum, so far so good. Many thanks.