MTH PS2 3V F-7 takes off

MTH website has following online manual for 20-20053-1

http://www.mthtrains.com/sites...ction/20dl16148i.pdf

Page 7 explains the polarity switch - it's for 2-rail operation and flips the polarity of the DCS command signal so you can face the engine either way on the track.

As for the functional problem, after fixing the frayed wire did you happen to swap boards yet again?  Seems you can learn a lot if the lack of directional control and lack of sound follows the chassis or the board.

If you aren't interested in DIY component-level repair, GGG is the guy to send it to.

Ok, Need to step back and ask if you are running the lead by itself or did you have it set up in the ABA configuration?

I assumed you were just testing the Lead A.  Now that the wiring issue may have been found, you might have a blown audio amp.  When you say no direction control, does it move in one direction with throttle control or no movement?  The lack of movement can be the motor FET went bad, or some other issue on the board caused by the shorted motor lead.

You also want to ensure solid connections on the joints to the small board at the rear of the engine, because that is the signals to the slave engine.  Of course we need to get the lead A working correctly first.  G

G,

I am running lead only, and will not be running the slave with it. I can remove the wiring completely. The locomotive responds to the thumbwheel in forward only,and it is not responding at a slow speed.  I could not get it to change direction, and did not here a click when I hit the DIR button.

Thanks,

Scott

Needs to be seen by a tech.  May have tach reader issue, plus and damage caused by the short.  G

The previous short is not a good thing, it probably has some sort of electronic issue at this point.