non-operating rear coupler

If there is a "sound effect", the board is getting the signal, but if the coupler does not even buzz or vibrate it indicates that no power is being sent from the board. If if vibrates/buzzes,

there is a mechanical problem with the coupler mechanism.

I received a Legacy U28C recently with a buzzing but non-opening coupler. I kept hitting Uncouple and nudging the knuckle - gentle pulling, plus a solid thump with my finger every so often. It now works. Was stuck. A little graphite dry lube is good.

But - if there is no buzz: coupler unplugged from board (remove body to see)

                                   broken wire on/in/to coupler (unplug and test -coupler only- with

                                   a little DC)  

                                   bad circuit on board (new board)

Typically the truck needs to be removed to remove the coupler, but maybe the pilot

will do. I'm not familiar with the Trainmaster's architecture, but they are all pretty

much the same, at least they used to be.

Removing and re-installing the coupler is not hard - it just takes patience, a small screwdriver to remove the retaining clip (watch that spring!) and common sense.

Re-installing is the same, plus pliers (for snapping the ring) and typically a healthy dose of words we don't use here.

Thanks for the reply...I do get uncouple sound effect but no buzz or action.  I too had another engine that buzzed but had a stiff coupler action.  I wish this one was just had that problem too!