Help diagnosing problem with MTH engine

It could be dropping into neutral due to a weak battery.. Command engines will run with out a battery but the slightest power interruption will drop the engine into conventional neutral..

Battery test..... How long do the sounds continue on after track power is shut off?

Gregg posted:

It could be dropping into neutral due to a weak battery.. Command engines will run with out a battery but the slightest power interruption will drop the engine into conventional neutral..

Battery test..... How long do the sounds continue on after track power is shut off?

Gregg, thank you for the reply. The sounds continue a fair amount once power is shut off. This is the only MTH that I own that takes two double a rechargeable batteries. I purchased it that way, and according to the manuel, that is correct.

 Looked up the product number. Engine has a wire tether. Any chance the random spots happen to be on a corner ? This is when the tether has the most strain on it.  Often times pushing the engine changes the tethers position and it regains its connection.  The motor leads I believe are in the tether. Not sure which pin or colored wire. This may explain why all the functions work except no movement. The tether could have a bad connection, broken wire internally,  or the pins soldered to the pcb could be loose at the solder joint and need to be touched with an iron.

 This is all hard to see while the engines running down the track. This is where a roller stand comes in handy. You can move the tether around and see if it can duplicate the problem. I'd start by making sure the wheels and pickup rollers are good and clean. Your other engines running fine seems to rule out dirty track.

Are you running conventional or command?  That would matter.  The fact it starts moving again after 5 seconds is weird.  Smoke, lights and everything works when it stops?  Can blow whistle or fire coupler when stopped?

You can clean wheels and pickups.  I would also check tether connection.  If you move it around does it effect operation.  If so, either bad wire in tether, or bad solder joints at the engine side connection (PCB).  G

Overloading the engine with tooo many cars  could cause the shut down. Does it happen with engine only?

Dave_C posted:

 Looked up the product number. Engine has a wire tether. Any chance the random spots happen to be on a corner ? This is when the tether has the most strain on it.  Often times pushing the engine changes the tethers position and it regains its connection.  The motor leads I believe are in the tether. Not sure which pin or colored wire. This may explain why all the functions work except no movement. The tether could have a bad connection, broken wire internally,  or the pins soldered to the pcb could be loose at the solder joint and need to be touched with an iron.

 This is all hard to see while the engines running down the track. This is where a roller stand comes in handy. You can move the tether around and see if it can duplicate the problem. I'd start by making sure the wheels and pickup rollers are good and clean. Your other engines running fine seems to rule out dirty track.

The random spots are both on straight tracks, as well as curves. I spoke to a buddy of mine last night, who happens to be a certified tech. He echoed the same thing(s) you said. It is most likely the solder joint. I really appreciate your input.

Regards,

Greg

GGG posted:

Are you running conventional or command?  That would matter.  The fact it starts moving again after 5 seconds is weird.  Smoke, lights and everything works when it stops?  Can blow whistle or fire coupler when stopped?

You can clean wheels and pickups.  I would also check tether connection.  If you move it around does it effect operation.  If so, either bad wire in tether, or bad solder joints at the engine side connection (PCB).  G

I am running comventional with a Z-4000. Yes, when the engine stops, everything still works. Whistle and coupler work fine. I did happen to clean the wheels and pickups. I really appreciate your input.

Regards,

Greg

Gregg posted:

Overloading the engine with tooo many cars  could cause the shut down. Does it happen with engine only?

Yes sir, with this engine only. I had it pulling about 15 freight cars total.

Regards,

Greg

Continuity between all center rail rollers??? test off the track.

Zero in on the tether connections, just touch the solder iron to each of them. We had a Milwaukee Road engine at the club that would do the same thing. The bad joint would cause heat, and would open the circuit. After it cooled it reconnected and continued to run for a while. Then repeat.

I had one do the same thing that yours and Choo Choo Paul's was doing. it was a solder joint on the locomotive side (PCB) .....kept running it with the shells off until finally I saw a tiny arc off the PCB.....soldered it back up, all is well.....It was one of the motor feed wires. if I nudged the engine/tender, it would start moving again, the nudge was enough to re-establish contact ...and off she went for a moment....still moving forward cause there was no interruption in track power. the locomotive still thinks its moving, even though there is a loss of power directly at the motor....hope that makes sense....

Gregg posted:

Continuity between all center rail rollers??? test off the track.

yes sir.