# LGB-2-6-0 motor problem



## rntfrmme (May 23, 2013)

I need everyone to put on their thinking caps for an issue that I have with an lgb 2-6-0 locomotive.

The loco in question had a bad motor. I know this because with almost full throttle the motor wouldn't run unless you bumped it by hand. I bought a new motor and it works fine. Well, sort of. lol

With the assembled motor block on my bench and power attached to the motor leads it runs very smoothly forward and reverse. When it is installed it will only run in reverse, smoothly like it should. In forward, firebox flickers, headlight comes on but no motor. Where should I look to solve this problem? three of us are scratching our heads over this and wondering if we missed something obvious. Would a bad board cause this issue?

Thanks for your help, I check in periodically during the day so bear with me if I don't respond right away.

Bill


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## Garratt (Sep 15, 2012)

Which LGB 2-6-0 model is it? The USA styled one with tender? Analog or digital sound?

Andrew


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## rntfrmme (May 23, 2013)

The usa styled one in a D & RG style. I believe it has analog sound.


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## Garratt (Sep 15, 2012)

It maybe best to quote the model number as there were quite a few different models. 
I know there were differences in the wiring for the digital sound ones.
Is it 2018D Red and green Number 18? I have the same.
Or 21181 Black boiler Number 19?

Andrew


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## Garratt (Sep 15, 2012)

Try testing it on it's side touching the wheels with some wires then do the same on just the contacts.
Do you get the same result as on track?
Does the rear tender light work when plugged in and running in reverse?

Andrew


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## Greg Elmassian (Jan 3, 2008)

Something is very strange, like a miswire of the motor on the wrong side of a diode for directional lighting.

Is this a 3 wire or a 4 wire motor block?

Greg


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## Garratt (Sep 15, 2012)

I was thinking similar Greg.
Here is a manual for the 2018D. Same wiring for 21181.
http://www.lgbworld.com/service_manuals/2018D-1.PDF

LGB did something weird with the polarity colors to the tender. The OP may have been stooged somehow. See below:
http://forums.mylargescale.com/21-rolling-stock/67098-why-do-old-lgb-mogul-tenders-appear-miswired.html

Andrew


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## Greg Elmassian (Jan 3, 2008)

Looks like a 3 wire block, so there would have to be a diode between the 2 wires that are switched with the motor on off switch.

The diagram suggests that the 3 wires go directly to the tender plug, but they must go to that #49 part since that is where the headlight and smoke unit connect.

Does this loco have the slide switches for lights and motor and smoke on off?

Greg


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## Dan Pierce (Jan 2, 2008)

Tender plug on LGB 3 wires to the tender have 2 track power wires and one wire for the rear light on coal tenders.Rear light references one track wire for the light!!. (Wood tender has no light but does have the wiring).

Motor block has 3 wires, one rail is tied directly to the motor, the other 2 are for the rear switch should be on highest number (all the way to the right as viewed from the tender).


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## rntfrmme (May 23, 2013)

First off, thank you for the responses. The loco is a model #26194. The motor block has a four prong, flat plug that can only be installed one way. I have determined (I hope correctly) that the out side leads go to the motor and the inside two are from the pickups to the circuit board. 

Garratt: With the assembled motor block on the bench applying power to motor leads it works fine, forward and reverse. After installation it only works in reverse, although the front light and boiler lights work fine come on when in forward mode. No hum, no motor noise, nothing from the motor.

By the way, reversing the motor in the block will allow it to run forward, but not in reverse with the lights coming on opposite of the motor direction as expected.

I hope this helps. Thinking out loud, I wonder if testing the motor plug might help. Applying power to the pick up side and then reversing polarity, simulating a direction change for the motor. If polarity reverses, or not, it might tell me if the problem is elsewhere. Hmmmmm......suggestions?

Bill






Bill


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## Greg Elmassian (Jan 3, 2008)

It's got to be in the electronics, since you have proved the 4 connections to the motor block work.

In the "4 wire" motor block, the track pickups and the motor pickups are all isolated from each other. So since the motor runs, both motor wires in the block are fine. Since the loco moves on the rails, both track pickups are fine.

So somewhere there is a diode between one of the track pickups and the motor. I was under the impression that the motor on/off switch was a single pole single throw, or a single pole double throw, so it should only be interrupting one "side" of the motor connection.

Something is really strange. You can try applying power to the motor plug (wires from the motor block), but I'm pretty sure that part is ok.

Greg


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## rntfrmme (May 23, 2013)

Greg,

I tend to agree with you. I hate being a "parts changer" type of mechanic and like to accurately diagnose the problem before buying parts. What you suggested about the electronics was my gut feeling but I wasn't sure.

Bill


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## Greg Elmassian (Jan 3, 2008)

Does the motor control switch actually enable/disable the motor powered from the track (test in the direction it runs of course)

That might give a clue.

Greg


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## rntfrmme (May 23, 2013)

Greg,

I will try that and see what happens.

Bill


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## Dan Pierce (Jan 2, 2008)

26194 is a digital with digital sound in the engine, wires going to the tender are:
2 for track power
2 for rear light
2 for speaker.

It could be the MTS board needs a reset, cv 55 to 55.

If you are analog only, this reset can not be done.
Also if you have pulsed power of any kind the decoder may act strange.


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## rntfrmme (May 23, 2013)

Dan,

Its always good to learn. Mine has the six wire plug as described. Now I need to figure out how to reset the board. I'm analog only. ugh!


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## Dan Pierce (Jan 2, 2008)

Join a club in Vegas and someone there should have a DCC system and can do the reset.

Or, if you know how to take the engine apart, you can send the board (actually the metal plate with both boards, bottom board is sound, top is DCC.to me to check it out. 

I have fixtures to test out the LGB onboard decoders like the one in your engine.


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## rntfrmme (May 23, 2013)

I do belong to the club here in Vegas. I need to find a member who can test it. Hmmmmmm.


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## Dan Pierce (Jan 2, 2008)

On another note, the DCC decoders can turn off analog operation with CV 29. The reset will turn analog operation back on. Again, setting CV 55 to 55 will reset the original LGB mogul decoder for analog operation.


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## Greg Elmassian (Jan 3, 2008)

Still, no DCC setting can explain running in one direction and not the other.

Greg


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## Bill Swindell (Jan 2, 2008)

I have seen this before. I believe that you might have a problem with the board in the locomotive. Try to temporarily jumper the 2 wires that are next to each other on the motor block. I think you will find that the engine runs properly in oth directions.


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## Greg Elmassian (Jan 3, 2008)

If I understand your suggestion Bill, you want him to short the track pickups to the motor leads, i.e. right pickup to one motor lead and left pickup to the other motor lead.

If there is a decoder in the loco (and we are pretty sure there is), and he jumpers these pins without disconnecting the decoder, he will instantly destroy the DCC decoder.

Greg


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## Dan Pierce (Jan 2, 2008)

Just unplug the 4 pin connector on the motor block and then tie the pins together with just the motor block.
Outer pins are motor, inner pins are track power. So, on a bench just the outer pins are needed to run the motor and with the cable to the engine disconnected.

Most LGB and all USA motor blocks have this wiring to the pins. LGB exception is the small motor block in the Olmana and Chloe where the outer pins are track and inner pins are motor!!


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## Greg Elmassian (Jan 3, 2008)

No offense, but a waste of time to try this. I've been following the thread from the beginning.

The OP states that if he reverses the motor leads, the loco will run in the opposite direction.

Therefore he has proved that the track pickups work and the motor works... the problem is PAST the 4 pin connector.

Think about it for a moment.

Still waiting to hear if the motor on/off switch operates.

(I'm guessing that part of the decoder is damaged)

Greg


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## Cougar Rock Rail (Jan 2, 2008)

I'm with Greg on this one. I think as the old motor failed, it drew too much current and fried part of the onboard decoder.


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## Dan Pierce (Jan 2, 2008)

If it is the onboard decoder, they are available but not neccessarily programmed correctly for the mogul.
LGB moguls need the voltages all programmed for 5 volts for the smoke and lights, look at LGB onboard decoders CV 49-60.


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## rntfrmme (May 23, 2013)

Thanks to all for responding. Sorry for not responding sooner, work got in the way of my playtime. I'm in the process of trying to find someone local who can help with the CV's. I don't have dcc or I would figure it out myself. All of the above posts help me with my troubleshooting and it does appear the board may have gone bad. As soon as I figure it out I will post with the final conclusion. 

Bill


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## rntfrmme (May 23, 2013)

First off, my apologies for not responding sooner. thank you to all who responded. After much head scratching and trouble shooting I determined that the motor was the problem. The motor had some issues that further testing identified. I replaced the motor and life is good. Forward, backward, fine speed control etc, all improved. Sometimes it can be the simplest things.......;-)


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## Greg Elmassian (Jan 3, 2008)

bad brushes? thrust bearing? too much fore aft play in motor shaft?

inquiring minds (still) want to know ;-)

Greg


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## Dan Pierce (Jan 2, 2008)

Greg, sometimes the lateral play in a motor will allow the end shaft to shift out of place, and LGB moguls have a 'long shaft' motor. Add to that that the axle shifts with a direction change which moves the idler gear also. Now the motor gear can be out of alignment enough to catch the side of the idler gear and stall the motor, and eventually strip the plastic idler gear. This will occur in only one direction.


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## Greg Elmassian (Jan 3, 2008)

Dan do you have a picture illustrating this, I think I get what you are saying, the long shaft deflects enough to the side to hit a different gear. which way the shaft deflects clearly is different depending on motor direction.

Is that it?

Greg


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## Dan Pierce (Jan 2, 2008)

Greg, the Mogul motor drives an idler gear and the idler drives the axle gear.
The idler gear can shift a little but the wear on the motor end shaft will cause it to move a lot and catch the side of the idler. 
Also the front axle has a lot of side play and can catch on the side of the idler. Sound moguls do not have this issue in the rear axle due to the added parts for chuff sensing, very limited side play, but non sound moguls will have rear axle side play. 
So, it is very important to have Mogul axle gears centered, and I add a washer to the idler shaft to limit side play on it.


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## Greg Elmassian (Jan 3, 2008)

Thanks Dan, that's a great explanation. I quoted you on my site, since it's not really obvious at first.

Greg - 159


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## rntfrmme (May 23, 2013)

Hello all. When I tested the motor the first time out of the loco it seemed to work fine, that is what led me to believe the board might be bad. After letting it sit for months i decided to give it another look. when I tested the motor at different voltages it became apparent that is was running very erratic and not smoothly at all. Lower voltages it wouldn't turn at all, then suddenly take off as voltage increased. Replacing the motor solved the issues. Honestly, i am not sure if its the brushes or not, I have never figured out how to remove and inspect them without destroying the motor. Thanks to all that responded. I did not notice a lot of side play in the shaft which can also cause multiple running issues. Bill


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## Greg Elmassian (Jan 3, 2008)

Thanks Bill, this thread will serve to help others as well as myself.

Regards, Greg


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## SophieB (Nov 22, 2015)

rntfrmme said:


> ...Replacing the motor solved the issues. Honestly, i am not sure if its the brushes or not, I have never figured out how to remove and inspect them without destroying the motor. Thanks to all that responded. I did not notice a lot of side play in the shaft which can also cause multiple running issues. Bill


I had similar symptoms with a first gen LGB 2080D engine. It ran fine in reverse, took a lot of volts and a nudge to get it moving forward.

I found directions for taking the motor apart here:
https://www.gscalecentral.net/threads/lgb-motor-service.163076/
and here:
https://www.gscalecentral.net/threads/lgb-motor-repair-and-testing.1237/

My problem ended up being that the motor brushes were frozen and the commutator very dirty. Ours was the older style motor so the brush holder assembly was pretty easy to take out.


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