Lionel 8141 Help

[ben10ben]

I picked up a Lionel 8141 yesterday for next to nothing, and I can't get it to run.

To save you all the trouble of looking it up, this is an MPC 2-4-2. It is powered by a Pullmor motor spur geared the wheels with a double wound field core and two position e-unit. It has a smoke unit and headlight, and comes adapted to use a sound-of-steam tender.

So far, I've cleaned out all the excess oil and grease, burnished the e-unit contacts, and replaced the brushes. The brushes installed were the same diameter as a standard brush, but tapered down to a contact surface with the commutator about the size of whistle motor brushes. I installed the normal brushes, which were all I had on hand. The mechanism moves relatively freely, although it does seem a bit tight to me(nothing at all like my 675).

When power is applied, the motor buzzes and vibrates loudly, as if it's trying to move. The wheels will occasionally turn a small amount when power is first applied(probably the equivalent of 1/3 of a motor rotation), and sometimes will turn very, very slowly. When set on a piece of track, the vibration is sufficient sometimes to make the engine jump a half inch or so at a time without the wheels turning.

Does anyone have any suggestions for what could be wrong? Thanks in advance for any help.

[lionelsoni]

All I can think of is that there is no field excitation. This could happen if the field common were grounded to the frame or if both of the field wires to the e-unit were inadvertently connected together, so that the flux is cancelled.

I would first disconnect all three field wires and check resistance to the frame, which should be infinite.

If this is okay, I would try to run it without the e-unit. The armature and one of the two field coils should be in series, something like this: Pickup to brush, other bru***o field common, either other single field wire (but not both!) to frame.

[brianel027]

In addition to what Bob wisely suggested, after you cleaned all the gears did you relubricate everything? I would also use some TV electronic spray cleaner to clean the e-unit inside. Those mechanical e-units are brilliant in design but can be pesky, especially if the loco has sat around in a damp, musty and/or dusty attic or basement.

Also a note of caution: the circuit board in the tender sits on a piece of foam to prevent it from making contact with the metal frame which could fry the board and replacements are unavailable to my knowledge. Pull up the old piece of foam which disintegrates over time and replace it with some fresh and new. Also there should be center rail roller on the no roller pickup assembly on the tender... just the contacts for the wheels: this is correct.

[ben10ben]

Bob and Brian,
Thank you both for your help.

Bob,
As per your suggestion, I disconnected all three wires and checked for continuity to the frame. I then completelty separated both coils and checked for continuity between the two. Both were okay(infinite). I connected one of the coils in series with the brushes, and got the same result. Do you have any other suggestions for what's wrong?

Brian,
I did indeed relubricate with a plastic compatible oil and grease. I generally reserve contact cleaner on the e-unit for sticky ones. I have sort of sworn off using tuner cleaner unless absolutely necessary since the telephone dial I sprayed with it that cost me many more hours worth of work getting all the oil out. Thanks for the suggestion, though.

[lionelsoni]

All that comes to mind now is that one of the field coils is shorted. Unfortuately, that would prevent it from working with either coil. You might be able to detect a difference in resistance between them. However, if it's only a few turns that are shorted, there would be very little effect on resistance. In either case, you may imagine that rewinding the field coils is very difficult.

[Anonymous]

Simple answer - take it to a Lionel service station.

pax

[trigtrax]

Since you've used the wrong brushes I would check there first. There has to be a reason they've reduced the diameter at the contact point. That violent vibration might be the armature being switched from fowar to reverse.

[lionelsoni]

Too wide a brush might cause arcing and heating but would not reverse the motor nor even change its operation much.

[johnsgg1]

Sounds like one of the windings on the armature is shorted. The indications are as you describe. A short turn of the armature, then stop. Any momentum (from a good push) will result in severe vibration - then stop. Check for continuity from one armature plate to the next.

[1688torpedo]

Hello Ben ! If all else fails Olsen's Toy Trains has those motors in stock.Not sure what they cost.Their phone number is [phone].Good luck.