Technical

This is a carry on from my previous post but due to this being a new fault I am putting as a separate post. Maurice has asked me to post this.

This is equally applicable to both the A4 and A3 locos.

My A4 Mallard nearly new was not responding properly to the regulator inputs. This could be a stiff regulator shaft, dirt build up on the regulator faces, compression of the superheater gasket being compressed into the regulator barrel. On my nearly new Mallard it was none of these but magnetic material sticking to the motor magnets blocking the clearance gap. This is worst in one motor direction than the other. Making the motor go backwards can clear the fault a for a short while.

The source of this magnetic material is a mystery, did the wheels pick it up and why only on one of my locos. I blew it away with compressed air and decided to measure the gap between the armature and magnets. one side was over 3 thou of and inch the top side less than 1 thou. The magnet had de laminated from the steel motor casing causing the magnet to touch the armature and make the magnetic material particles by rubbing the magnet. Check paint on armature is free from scratches a certain indicator something is wrong. I squeezed the magnet back into place with long nosed pliers then ran a little high temperature super glue in the joint between the magnet and the steel casing. Glue was Liquid Weld obtainable from the model aircraft shows around the country. This glue sticks steel and is not brittle and stands high temperature. Loco now runs superbly and completely predictable counting the control clicks up and down.