Light on but no movement?

[Rowenjosh]

I am new to the forum.
We have a Spectrum Mallet and a J Class 4-8-4, both run on different layouts and now both present the same problem.
When we apply power, the front light shines but the locos will not move. The wires between the tender and rear of the cab on the J Class have lost their black paint, but that is the only thing I can see which might be the problem.

Any help greatly appreciated.

[NarrowMinded]

Do these loco's currently run on other layouts? Do other loco's run on the layout these two have problems on? Are they dcc equiped? Do you run DC or DCC a dcc loco not set to run on dc usually will still turn the headlight on when power is applied

NM

[Rowenjosh]

Thanks for the reply.
Both locos have previously run very well.
Both are N Scale, neither is DCC.
They run on DC layouts.
Other locos run on the same layouts without problem.
Thank you again.

[Jim Banner]

The lights are on so power is getting to the locomotives.  That leaves only two possibilities.  Either there is an electrical problem such as power not getting to the motor or the motor is bad OR  there is a mechanical problem such as the motor or the gears or the drive rods are jammed up.

Electrical problems are best traced with a meter or a grain of wheat bulb, following the path of the current until you find out where it is interrupted.  If you start at the motor and work back to the wheels, you will know right away if power is reaching the motor because a meter connected across the motor connections will show a voltage or a bulb connected the same way will light up.  If they do not, work back toward the wheels to the point where they do.  If power is reaching the motor and it is not running, check to see if the motor is burned out.  A resistance check with either the meter or the bulb with a 9 volt battery in series (done with the locomotive off the track!) will show whether the motor is burned out or not.  If the motor is okay and is getting power, then the problem is mechanical.

Turning the motor gently by hand often will show where any binding occurs.  If any of the wheels have twisted on their axles, the binding will almost certainly be in the linkages (drive rods etc.) and the wheels will have to be put back in quarter.  Quartering is a long subject in itself and is best done with a quartering jig and the help of someone who has done it before.  If there locomotives were ever run on a track set on a rug, check around the axles for lint/pet hair/etc. that may be binding the axles.  Best bet here is to pick all the lint/hair/etc. out with a pair of sharp pointed tweezers.  This is a slow, tedious job that is sure to remind you not to run on the rug again.  Re-lubricating the locomotive with the proper plastic compatible oils is always a good idea when you have the locomotive opened up and especially so if lint/pet hair/etc. has sucked all the oil out of the bearings.

Good luck, take your time, and try to enjoy the process as you learn more about the innards of you locomotives and how to fix them.

Jim 

[NarrowMinded]

smaller scales are more likely to have problems with lube gumming up after they sit for extended periods, they likely just need a good cleaning and lube, have you tried applying light downward pressure on the loco while moving it back and forth while applying power? This can some times free up some sticky gears and motors.

NM

[Rowenjosh]

Thanks for the advice. The locos haven't been on a rug or carpet but will work through the other suggestions.

Many thanks.

Rowenjosh