MTH Proto 2 engine over heating then stops

Reverse the wires to the motor and check again. If the problem stays, then it is possibly a motor problem. If the problem is now in the reverse direction, then there is a board problem. If you are handy, you can also swap the motors and boards out to isolate the problem since you have a second identical engine.

Larry

If you choose to reverse wires to the motors you can pop out the yellow and white crimped wires by slightly bending up the retention clips on the 5-pin motor connector.  Then swap and re-insert. No soldering/cutting/splicing required.

Another idea.  IF you have an overheating problem, the excess energy has to come from somewhere.  So if you have a Z-4000 or similar current-indicating transformer, is the current is substantially higher in reverse than forward for the same speed?  I suppose you could also compare numbers with your known-good engine.

I assume you didn't run the engine in conventional with full command-voltage on the track?  For an apples-to-apples test, you can run the engine in command-mode with, say, only 12V or so on the track and send a DCS speed command that corresponds to a 12V conventional speed (about 20 sMPH).  This might reveal more information about the conventional vs. command behavior difference.

Hi stan2004... As soon as I am finished doing some computer work I will reverse the wires as you suggest. 

In general, I operate using the MTH TIU at fixed 18V. For the conventional test run of the problematic engine, I swapped the power wires and ran it through the variable input/outputs of the TIU. The engine operated normally as any conventional engine does.

Back to 18V fixed and the forward random stopping resumed.

I do not believe the engine is overheating at all. I think the board has developed a glitch after another train that I was running on the same track as the Rescue 2 derailed on a switch. Ever since that derailment, spark and circuit breaker power shut off, Rescue 2 developed the random stops in forward motion problem. But it does seem related to the board sensing the heat of the engine. In reverse, it never stops. In conventional mode, it never stops. 

After I reverse the motor wires as you suggested, if the problem continues I will ship the loco to MTH for repair. I am sure they can fix the issue.

TrainLarry: I won't cannibalize my other Rescue 2 engine simply to fix the first one - LOL! I want them both up and running after Halloween ends, but at least I will have one while the other is being repaired.

Thanks for the suggestions.

Terrence, I did not mean for you to swap out the parts to fix the bad engine, just to use known good parts to isolate the problem on the bad engine, after which the parts would have been returned to their respective engines. More than likely the board went bad, possibly caused by a momentary voltage spike during the derailment. If that is the case, a Transient Voltage Suppressor in the power supply line to the track would have probably saved the engine.

Larry