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Discussion Starter #1
I have a Bachman Mogul #81492, that doesn't move in either direction with full power on a test track.  Have headlight, and fire box flicker.  Where would you start to check.  I have never opened a Bachman loco.


Mike 
 

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Just a guess, as I don't have one of those, but, on the very front, look close at the smoke-box cover, around it are several bolts, one bigger or different, Rotate it to unlatch the smoke-box door which should have a hinge and swing out to one side. Fiddle with the switches hidden in there. They may be labeled NMRA or MOTOR or SMOKE.


If not there, check for a switch inside the cab .


If not there, then wait a few minutes for someones informed answer.


 
 

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Is there any indication that the motor is trying to turn? (which would indicate a mechanical fault as opposed to electrical). In either respect, the boiler is held onto the chassis by a screw that runs up through the center of the steam chest (accessible between the cylinders) and--I believe--four screws on the side of the firebox. You'll also need to take the boiler stays off the front (four REALLY TINY) screws on the platform. Put them back in place once you pull the stays off, otherwise you'll never see them again.

This will give you access to the motor leads, so you can make sure that's working properly. The control electronics are in the boiler, so you'll have to remove the smokebox front (if I recall, it just pops off), and pull the board out there. I haven't the foggiest clue what goes where on that board, but the power in and motor out are fairly identifiable.

Good luck.

Later,

K
 

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Mike, It is really hard to say what the problem is, but it could be a loose wire to one of the switches on the smoke box front..  I believe you can gently pull the entire front off to expose the wiring behind the switches.   Another possibility is that the noise suppression device is burned out.   It is attached to the front of the motor.  You can remove the bottom plate and check for loose wires, if all looks good use a continuity checker to see if you have power at the two leads that connect to the noise suppressor.  if good then check directly on the motor leads.  If it is dead there then the problem is the noise supressor.   You cane carefully remove the noise supressor and solder the leads directly to the motor.   The noise supressor is not needed for operation and is put on to meet FCC requirements.

If you feel it is all over your head, or the loco is brand new then contact Bachmann for service under your Warranty.

I believe TOC posted this fix in the old forum in great detail.   You can also do a search on the Bachmann Web site..

You may want to try a search on the Archive fourms for the fix.  

Good luck!!
 

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Mike,

You have had some good responses. Obviously if the loco is brand new, maybe a factory fix is in order. If not new, and you feel up to getting into a fix, here's where I would go: While not knowing what if any control system you are using (like DCC, battery, etc.), assuming basic principles, either the motor is getting power (and not operating), or it isn't getting any juice. The track pickup is not an issue (you are track powered? From reading your post) as the other functions are getting power. Kevin asked if you can hear the motor trying. If you cannot, then trace the power flow from AFTER the track pickup, through all the switches, to the motor.

There are several weak points to look for: All solder joints from the main PC board, through the switches, and the actual motor connections themselves. Solder joints do fail! Without knowing if your loco is new, or has been DCC'd, etc. it's hard to be more definitive. For example, if I knew that you were DCC I could rule out a bad filter board on the motor, as you could not have that there and still work in DCC. It would have to be removed at some point.

Kevin's advice on taking the loco apart is spot-on, with two exceptions: There are SIX screws (3 per side), and the one he mentioned under the smoke box. The rear screws are hidden behind the rear drivers and are difficult to see without working the suspension a bit. Further, in order to separate the cab/boiler assembly, you will need to remove the Johnson bar screw which joins the rod connected to the control lever in the cab RH side to the chassis. This is a brass screw, is difficult to see and remove, more difficult to replace, and is non-magnetic, so be careful! Unfortunately, to check your wiring, you're going to have to go through this exercise.

If I can be of further assistance, don't hesitate to PM me. I have two of these Moguls and have been all through them.

Regards,
 

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Discussion Starter #7
The motor does not seem to make any try to move anything,  I looks like I will just have to open it up and try to trace it out from their.  Looking at the bottom of the loco, it looks like a job to dissasmble, your responses will be some help.  By the way this unit is used, and I don't know the history.  Does anyone know the function of the electronics board powering the motor.  Thanks all for the help.
Mike
 

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Discussion Starter #8
The switch assembly and main electronics board easily pulled out of the front of the boiler.  There is nothing with obvious damage or any loose wiring noted.  There is power coming out of the directional switch, so it is on to looking at the motor.    After examination from the bottom of the loco and removing some tiny screws, I am able to pivot the motor and gear box on the center drivers.  Examining the circuit board on the end of the motor it appears the two resistors have been quite hot.  I removed, using a soldering iron, the circuit board from the end of the motor.  Then applied with alligator clips power directly to the motor and the motor was determined to be defective.   The question now is removing the motor.  It appears to be screwed in to the gear box from the opposite end of the circuit board.  I see no way to remove those screws.  Then how hard is it to get a replacement motor?          Mike  
 

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IF you have been using a PW supply of any kind, or some versions of DC, the motor noise suppressor that I have been telling folks for many years to remove has toasted itself.
The "resistors" are "inductors", or "chokes".
Sometimes the heat generated takes the plastic brush end of the motor out.

Now, disassembly is not easy.
You will need to pop the 10mm caps off the driven axle drivers, remove the screws and drivers.
Draw diagrams or take pictures as you progress!
Re-insert one screw in one end of the axle, and grab it with a pair of pliers, and pull the axle out.
When you do this, all the valve gear assemblies will fall out.
Take notes and drawings!
You should now be able to lift the motor and gearbox out of the chassis with the bottom cover still removed.

Take the side cover off the gearbox.
Remove the screws inside the gearbox that hold the motor in place.

This is done by memory, so hope I didn't forget anything.

Now, you get to find a replacement motor.

Bachmann may be of no help.

However, it's the same motor used in Big Haulers, Heislers, Climaxes, 2-8-0's, Porters, smaller 2-6-0's and 4-4-0's.
The differences are the shaft length and the gear.

If you are capable of changing gears and whacking the shaft to length, you're home free.

If not, send it back under warranty if new.

If you get in a bind, e-mail me, or call.
Phone number is in the GR ad.

TOC
 
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