Lgb 2085d Mallet Problem

R

Robert Bianchi

Registered
I have a slightly run LGB 2085D Mallet Loco that I inherited from my brother. He bought it in 1985 and put it in a showcase with very little run time. I just bought a new LGB 5 amp transformer and controller and wanted to run the engine. It runs fine at slow speeds, and with loads on the engine. However, if I attempt to run it at higher speeds, it shorts the transformer indeterminently. It will run for maybe 10 feet and then short. If I then run it in reverse, it will run for awhile and then short. If I then run it in forward, at a moderate speed, it will short. However, if I run it at low speed, it runs fine.

Does anyone have an idea what is causing the short or where I should start to look for the problem?

Thanks, Bob.
 
bad motor that runs but draws too much current.

motors can go through damage that allows them to run what appears normally, but they draw a lot more current... the fact it runs and then trips the overload supports this theory.

Not really a short... but an overload condition that draws too much current at higher speeds.

Also many circuit breakers operate on heat... a dead short opens them quickly, an overload can take a while longer.

Greg
 
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I agree with Greg, but if it has been in a showcase, it may be the grease has dried up a little in the motor-blocks..
Put the loco in its' polystyrene packing. Turn it upside down, to get at the underside.
remove the base-plates on the motor-blocks and see what state the grease is in. If necessary, remove the congealed grease, and replace..
Please be careful not to move the axles relative to each other, as even one tooth out can cause the motion to bind. - This would exacerbate your problems..

I would then run the loco on rollers (if available) at a medium speed for an couple of hours in each direction. - it could be it had so little running, the whole loco is just s little stiff?
 
The brushes in side the motor may be seized.
As said above - almost certain to be a motor problem - even with very low usage. Sometimes a bit of use is better for them.
 
Hi all,

I really appreciate the rapid answers. The grease possibility was the first I considered before writing the inquiry. Since I'm really busy just now, it might take a little while to discover the actual problem, but I'll let all know how it turns out.

Thanks again.

Bob.
 
I agree w Greg.
Just had the very same happen to my own mallet. Out of the blue, so it seemed. One day fine, the next sluggish and slower.
Resistance/amperage draw grew with voltage, i.e. I could run it slowly with 2-3 amps, but it rose as voltage was raised. 2-3 amps btw, even with sound is too high. Should be about 1 no cars, on the flat.
Likely the front motor. Replace it.
The defective motor looked perfect. No amount of cleaning changed performance.
 
Thanks Steve. I'll first have to get a meter to measure the amp draw to be sure which motor is causing the problem. Btw, where do I obtain a new motor? LGB/US? Will also try good cleaning and re-lube. Interestingly, the engine will die at about the same voltage when run without cars or with 6 long passenger cars attached.

Thanks again,
Bob.
 
New motor - Garden Rail Outlet - the blue advert to the right of this page.About 40 quid.
 
Train li has the best prices I have found. And great service.

I am, by and large one to repair if I can, versus replace. Otoh, those tiny soldered wires put me off. Easy to go from "there's a chance" to oh s$&t!

Neil:
As for cleaning, I submerged it in denatured alcohol and applied voltage, removed from bath, blew it out with computer air, ran it to dry. No change. Housing got warm. Then, shot a touch of electronic lube cleaner. No help. No change.

I have great luck doing this with filthy over oiled motors.
Btw, I do not recommend the cleaner contact lube. It will work great initially, then the carbon dust builds into a gunk, and into the commutator shaft. I used it simply to see if I got a jump in performance, possibly the indicating a contact issue.

Btw, I don't know if my thinking is sound, but my past experiences tend to support my thinking of this being effective.

But...
Put in new motor, my black sound mallet runs as it should. And, it's off the " to do" list and I can be happy that my toy works.

The defective motor is the newer design, and while I did bend the end cap tabs, I skipped on pulling the worm off the shaft. And those wires soldered to the case. I can solder, but, pulling the gear and getting it back perfectly positioned was the straw.

I don't have replacement brushes, so I decided to spend the fifty odd bucks, versus screwing around for two plus hours to make Sure it was Broken. On the Older versions I have had success. Not up to the new ones, at least not yet.
 
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Hi all,
Finally managed to get to it. Removed the base plates and examined the gears. No gunk. Was only lightly oiled as per the German instructions. Cleaned all (including the inner wheels where the brushes ride - lots of carbon there so had been run some before being showcased). Problem still exists. Getting meter so can measure current draw to determine which motor is bad.

Thanks to all of you for helping so far.

Bob.
 
Greg Elmassian said:
so now the thing to consider is why did one motor fail. Check to see if you overloaded the loco, but it would have to be prolonged abuse. Just something to consider so as not to repeat the situation.

Greg
Click to expand...

Not necessarily from abuse--I have seen almost new Buhlers fail. There was a bad batch of them (but I thought it was later than 1985) that failed internally and were perfect otherwise. I don't need to tell you where they were made. It seems to me that was in the early 2000's though--maybe one or both motors were replaced at some time already and got one of them? Either way, I think you're right that it's the motors and hopefully nothing has been damaged on the circuit board.

Keith
 
Thanks for the input Greg and Keith. My brother passed away last Nov, so no way I can ask about the engine. He was a lifelong IBM CE, so might have replaced an engine - don't know. Also, the engine was run only indoors and he had small layout, so probably didn't overload it. I'll let you know as the saga unfolds. Btw, any suggestions on how to confirm the gearing is in the correct positions when pulling the motor?

Thanks,
Bob.
 
Robert Bianchi said:
............

.............. Btw, any suggestions on how to confirm the gearing is in the correct positions when pulling the motor?

Thanks,
Bob.
Click to expand...

Bob, when you lift the motor out you may be able to mark the top-dead-centre tooth of each gear with something like a black sharpie, provided the grease doesn't get in the way. When you reassemble the gearbox with the new motor (or put the old one back if you don't find a problem with it in the end), you need to look very carefully at the wheels on both sides of the power unit, and make sure that they are exactly lined up (if they are spoked wheeels, usually one spoke will be near enough to vertical that you can use it to eyeball the alignment). If one gear is a tooth out, you should be able to see that the wheels don't exactly line up - raise the motor again and turn the offending gear one tooth, and check again. The motion rods on the power unit will keep the wheels ROUGHLY in alignment, but they always have enough play in them that the driven axles can get one or even two gear teeth out.
The process of making sure everything is correct here is called "quartering". If the quartering is out by just one tooth, it will make the power unit behave oddly - it may be sluggish or jerky, and the coupling rods may bind up in certain positions.

Jon.
 
I can say, simply, I do not overload. Very aware of the ramifications. A seven car train is a rarity, most being 3-5 , even w the mallets.
As parts are increasingly rare and pricey, I am extra careful to avoid stress. Wait until you need drive rods....

I have heard it is often the front unit which fails. Having noticed no slipping, nor feeling unequal weight, I have no clue why this is seemingly , a truism.
 
Thanks, Steve,

I normally use only 4 cars on my trains - also don't want to overload. I just picked-up the multimeter and, hopefully, will test the motor current loads - as you say: I'll try the front motor first.

Bob.
 
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