# "New" Used MTH locomotive sparking and getting hot. Advice?



## [email protected] (Dec 8, 2009)

I need a little advice on troubleshooting / lubing / prepping a used diesel loco. Keep in mind that I am complete newbie, and have never even opened up a loco.

A few nights ago I bought an older MTH Chessie Diesel set off Craigslist. I was told that it had less than 10 hours of runtime on it, and then had been cleaned and put back in the box for storage. It has likely been in storage for several years. The loco itself looks outwardly in mint condition. It has only the electronic horn, so ProtoSound or anything. It is this set:
http://69.20.67.75/content/30-4016-0

OK, so tonight I got this guy out of the box to test it out. I set up a small circle of track and my Z1000 transformer, and it ran well right away for a short time. Then I started seeing some sparking from the center rail on the front of the engine and it slowed down. I shut it off. Took it off the track and looked at it...everything looked fine, maybe dirty track? So I tried again starting at a very slow speed...increased speed a bit then saw some sparks, it slowed down, and I shut it off again. Now the center wheel and spring bracket thingy were very hot to the touch and I saw a little bit of smoke which looked like it could be coming from the motor. The rear center wheel was still cool and seemed fine back there. 

What should I do to assess the condition of this engine and get it ready to run?  Is there some sort of tutorial somewhere for troubleshooting/preparing an loco? I will be able to work on this over the weekend, so I'd like to have some idea what to start with.

Thanks a lot!
Rob


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## T-Man (May 16, 2008)

You have a short. It could be a wire,light, or the reverse unit because they are before the engine/motor. Jump your motor to see if it works. Use DC if it looks like a can.


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## [email protected] (Dec 8, 2009)

T-Man said:


> You have a short. It could be a wire,light, or the reverse unit because they are before the engine/motor. Jump your motor to see if it works. Use DC if it looks like a can.


OK, I will take a look at it this weekend. But what do you mean by "jump" the motor? Not sure what you mean about using DC though. Does it switch to DC to power the motor? I thought they were AC. 

Thanks T-man!


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## T-Man (May 16, 2008)

If the motor runs on a magnet it's DC. The e unit converts the AC with a bridge rectifier. With the rails AC they can send DC signals for bells and whistles. DC motors are cheeper too. Use wires from the transdformers and JUMP the Motor directly. It should be A DC one. I am fairly sure it is DC but I could be wrong because I have never seen it.


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## [email protected] (Dec 8, 2009)

T-Man said:


> If the motor runs on a magnet it's DC. The e unit converts the AC with a bridge rectifier. With the rails AC they can send DC signals for bells and whistles. DC motors are cheeper too. Use wires from the transdformers and JUMP the Motor directly. It should be A DC one. I am fairly sure it is DC but I could be wrong because I have never seen it.


Thanks for the info T-Man. I got it out again tonight to start looking into it and I switched back the reverse lockout and it ran fine. So I thought that might be the culprit, as I remember now it started sparking right after I locked the reverse out. So after some good runtime at different speeds, it still was cold and no bad sparking. So then I locked the reverse out again and it still worked fine. I will have to just give it some test time and keep a close eye on it.

As far as an AC/DC conversion, is there a simple way I could do this off my turnout's AC voltage? I would like to use that to drive the relay running the power routing to my siding tracks. I think you need some diodes and resistors or something? 

Thanks!


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## T-Man (May 16, 2008)

Look for exposed wires, grounding out.

The simpliest way to power just a relay on DC is to use a wall adapter. You will need a meter to check them. They vary in voltage, if you get a few in the 9 tp 12 v range, they will read 14 to 20v. Amperage may be an issue. The closer you are to 12 v the better . The is trail and error on you part. you should place a diode across the coil and prior to the pos feed. They are 14001. In your case a bridge rectifier would work 
First look at the power supply I made for 12 v and the relay withthe two diodes in the reverse circuit. I have powered it with an adapter. But I have a chip too, you just will have a relay. The relay is on posts 12 and you just barely see the the diodes under it. (The black box on the board on the right). You can get the adapters at Goodwill for a buck. The DC outputs are getting harder to find.
If you use the AC on your transformer a bridge rectifier would help but the voltage will be high. Some transformers have an adjustable AC output.
How is the relay being activated?

You are really asking about a 12 v DC power supply.

01-10-10

After some thought the easiest way to power the realy is to get a small DC transformer used by the HO group. I used a DC LIonel and adjusted the lever till I got 12 volts. Ironically I had used a Tyco and could not get a variable reading only 19 volts. I can't explain it. All you have to do is tape the lever in place. The Lionel transformer is a little different since you can reverse it by turning to the oposite direction. TDC was stop.


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## [email protected] (Dec 8, 2009)

T-Man said:


> Look for exposed wires, grounding out.
> 
> The simpliest way to power just a relay on DC is to use a wall adapter. You will need a meter to check them. They vary in voltage, if you get a few in the 9 tp 12 v range, they will read 14 to 20v. Amperage may be an issue. The closer you are to 12 v the better . The is trail and error on you part. you should place a diode across the coil and prior to the pos feed. They are 14001. In your case a bridge rectifier would work
> First look at the power supply I made for 12 v and the relay withthe two diodes in the reverse circuit. I have powered it with an adapter. But I have a chip too, you just will have a relay. The relay is on posts 12 and you just barely see the the diodes under it. (The black box on the board on the right). You can get the adapters at Goodwill for a buck. The DC outputs are getting harder to find.
> ...



Hey T-Man,
Unfortunately, I can not power the relay with a DC wall adapter or DC transformer. The voltage I want to use to power the relay coil will be coming off of the MTH turnout's remote switch inputs. 
Basically, the remote switch on the MTH turnout has a couple of lights in it to indicate the position of the turnout. So one set or the other of contacts has a 14V AC depending on turnout position to power the lights. If I can just convert this to like 12-14V DC and hook it up the relay, I can use the relay to divert power to one insulated siding track or the other. Thus, it becomes a power routing turnout. Does that make sense? So I just need the AC to DC part, and I should be good to go. 
Is a bridge rectifier a circuit I can build? Or is it a single component? I will do some research on that as well.

I have to say after tearing into the MTH turnout, I am pretty impressed with it's design. I like the way it uses 2 microswitches inside to cut power, thus not allowing you to burn out the solenoid by holding down the switch or pressing the wrong direction. It just does nothing on that side once its switched. Pretty cool design.

Thanks again T-Man.

p.s. BTW, that new diesel engine is running great. We set up a test track of 80 ft in the play room and its been running a few hours on and off today.


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