MTH reverser

Have you done any tests on a test bench using test leads to power the locomotive?

Does the motor run equally well in both directions when not on a track? (Not under any load?)

Yes,

I have put on the bench and tested. The exact same symptoms occur. The loco does run equally well in both directions, just stops in reverse after a second or about 12 inches.

Is it PS1, 2, 3 or Locosounds? That info will be needed,to identify and price the right board. If it is a board there are at least 2 guys on the forum that are wizards, with the boards. Also, because I'm electronically nearly illiterate, I'd probably pull the motor and run it in reverse, to eliminate the possibility, albeit small, that there is something wrong mechanically.

Which model.  Is this basic reverse unit, PS-1 or PS-2.  Can it be mechanical, the motor thrust changes and it can bind depending on the slope in the gearing.  Does it stop or slip the motor gear.  Lots of questions before an answer can be given.

To determine if this is electrical or mechanical measure motor voltage while testing on a bench.  If the voltage goes away it is probably board related.  If the voltage remains but the motor stopped it is mechanical.

Depending on the nature of an electrical fault it could be repaired at the component level, but we need to know which circuit board is in this model.  G

I'm not sure what a PS1, 2 ,3 are but this has no sound or control. just one PCB for the reverser.

Protosound  1 2 and 3 are MTH control systems. they add lighting and speed control.My first MTH loco had "locosounds", which was forward reverse bell and whistle. I've never seen an MTH with no sound. What is the model number on the box?

Never mind. you have GGGs attention. He will guide you through.

OK, I put my meter on it and there is no binding of the motor. I have some pictures of the PCB.

The voltage goes away on the motor in the reverse direction. I varied the transformer voltage and noticed that the higher the voltage in reverse, the faster it will stop.

From the picture, you have a 2-6-0 with electronic reverse. Has a air whistle.You may be able to repair.

Check the 4 power transistors on the board that they are all soldered on the opposite side of the board. Sometimes they come loose. When the engine should be running, giggle the transistors and see if it starts. At worst case, the board can be replaced.

 I don't think MTH has these boards anymore, but can be easily replaced with a different unit.

PS, I did notice a hot spot on the board right below the red plug. Check for a burnt foil trace on opposite side of board.

Excellent! Thanks so much for the troubleshooting. I jiggled the power transistors. looked all over the board for signs of burnt components, none. Checked continuity of the power transistors and verified good solder. Looks like I need a new PCB. It has SS11B on the reverse side. COMP on the component side. Any ideas where I could find one? This is a family heirloom so want to keep it.

If you want to see if someone, somewhere as a original MTH board, the part# is AC-0000003. A Lionel standard electronic reverse unit board will work fine in this case if no MTH boards are located.

Thanks much! I'm going for the Lionel PCB.

Sorry I am late to this.  Can be trace or either logic failure or commonly one or 2 of the motor transistors have failed.  Probably can be repaired.  Or as Chuck stated any basic DC reverse unit that is sized to fit.  I have Lionel 103 if you need one, or can try to repair yours.  G

Thanks GGG. I ordered a Dallee reverser and waiting arrival. I'll post how it all works.