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Hello, I have a 1991 Lehmann 92677 Lake George and Boulder "Rocky" train set that I have used as a Christmas train since new. Always been a little under powered for the number of cars I would like to pull, so this year bought a used powered tender. Ran fine for a couple of weeks, but now - while the tender still works fine, the engine "pulses" as it runs. Like it is getting slow AC power. Checked the transformer with a multi meter and the output is clean with no obvious power pulses. And the tender runs smoothly by itself. Checked the "feet" that travel along the track, even took off the bottom cover and everything looks clean and see no corrosion or broken parts. Any ideas on how to trouble shoot this problem would be greatly appreciated.
 

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Did the tender and locomotive run similar speeds when not connected originally?
If they did not you may have damaged the motor. I think they have a 7 pole motor and you may have blown one of them giving erratic running.
The other simpler to fix possibility is if you have removed the bottom cover at some earlier stage you have placed one of the axles one tooth out. The rods etc. are fairly loose but will bind slightly during the wheel's revolution making it limp along.
Rock each one to and fro a little to deduce if both the same and on the correct tooth. Removing the rods makes it easier to determine.

Andrew
 

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Check for hard grease on the gears, may be time to repack after 25 years.

John
 

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Discussion Starter #4
Did the tender and locomotive run similar speeds when not connected originally?
If they did not you may have damaged the motor. I think they have a 7 pole motor and you may have blown one of them giving erratic running.
The other simpler to fix possibility is if you have removed the bottom cover at some earlier stage you have placed one of the axles one tooth out. The rods etc. are fairly loose but will bind slightly during the wheel's revolution making it limp along.
Rock each one to and fro a little to deduce if both the same and on the correct tooth. Removing the rods makes it easier to determine.

Andrew
Before connecting ran them near each other but not connected and they seemed to run really close to the same speed. Had never removed the bottom cover before tonight. Engine had run flawlessly for 25 years. Just had to run with only 4 cars of the 5 I own as it would slip on my track (brass LGB track) if connected the 5th car.
 

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Divide and conquer. Remove other influencing factors. Electrical contacts, rods, gear teeth, lubrication etc.
Check the gear teeth are not worn and they are lubricated with good grease like John said. You need grease suitable for plastic gears. Don't over pack.
Try running without side rods in case there is a problem there with running gear.
Run some wires to the sliders with loco on it's side to see if motor runs smooth with no load. Rub finger on wheel to create load etc. You need to determine if it is an electrical supply/pick-up problem, gear drive/running gear problem or an armature winding/brush problem.

Andrew
 

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If it ends being the motor, be careful as this engine has the same part number for 2 different motors. One was round and the other has 2 flat sides. Be sure to ask when ordering this motor that it is a match.
 

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Does the discontinuous running coincide with the revolution of the wheels or is is much faster than that?
That should indicate whether it is the gear drive/running gear or armature that is at fault.
Interesting information Dan, I'll have to try and remember that as I have a few of them.

Andrew
 

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Discussion Starter #8
Problem fixed, I hope, thank you

So, took the bottom back off, pulled the drive wheels and axles, made sure everything was clean. Connected the transformer wires directly to the pick up skids and the motor seemed to run smoothly in both directions. Put everything back together but with the cab still off and tested it on the track. Worked great. Finished putting it back together, connected it to the tender and it is test running now on the full track circuit and seems to be running fine. Not sure what I did, but apparently fixed some kind of loose connection. Thank you all for the help and advice. Afraid this is a train that I only run about a month and a half a year as planes and pinball machines are my main hobbies. But thanks for being here to help.
 

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Good, all fixed then. I bought an LGB German mallet that was new old stock that was perhaps 30 years old or so. One motor was very stubborn and would not run at first then it did hesitantly. It took a lot of fiddling to get it up to speed with the other motor, laying on it's side. Eventually after some time they both ran fine. I suspect it could have been slight oxidization on the copper commutator impeding the electrical current. After all, it had not run for 30 years from new.

Andrew
 

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Garratt, if you look closely at the wires on the commutator you will find they are crimped.
I scrape the enamel wires and solder the open connections on the older motors.
 

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Discussion Starter #11
Wellllll, looks like I declared victory a little too soon, but not the same problem. I thought I had noticed during family Christmas gatherings and before the pulsing of the engine problem that once or twice the train seemed to just stop running, then started again. But wasn't entirely sure that a guest hadn't turned it off then back on. Last night, in letting it run all evening to make sure pulsing problem fixed, it did stop running on its own, then later started back up, then stopped again. Would I be correct in suspecting that the new tender is overloading / overheating the transformer? It did feel warm right after it stopped.
 

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Most controllers will cut out eventually when overloaded. What controller is it? Some LGB starter controllers are only 7VA or so which is really only good for a small single engine. They will run two but by the time you add plenty of cars ect. will be running at it's limitations. The LGB 50081 (120v) or 50080 (230v) starter controller is 20VA (about 1 amp) which only has two output terminals would be preferable without going the extra expense of a controller of several amps.

Another approach is a good 12 volt controller that's one or preferably two amps. The train will just run slower on the lower voltage which can be desirable anyway. Just depends on your budget.

Andrew
 

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Discussion Starter #13
Transformer

Looks like you got it on first try, my 25 year old starter transformer is 7 volts. So should shop for new one. Funny, just sold a bunch of Bachmann track and transformer, that I got second hand. Probably should have checked its voltage first. Will start shopping for new transformer.
 

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Your controller is is 0~21 volts @ 7VA (volt-ampere) which is another way of rating the capacity of the unit. VA is ambiguous though because it is measured somewhere on the dial of volts but not necessarily at the speed you wish to run it. It is about 0.5 amps.
That being said it is only good for a small single motor locomotive and a few cars for extended use so you need about twice or more than that for running two motors.
Remember it is the volts that determine the speed that the locomotive will run. Considering we don't usually run at full speed, a 12 volt unit will do just fine but will still need enough amps for running two motors.
It's likely the 12 volt one you sold was not much higher in amps than the one you are using if from a starter set.

Each motor will draw perhaps 750 ma at stall. The powered tender will draw more than the porter saddle loco. An LGB 1 amp controller will probably be OK if running lightly but only just. Dan may have a better advice here.
The 50081 unit below is 20VA or about 1 amp but has no accessory outputs.

LGB make a 5 amp unit but not cheap.
People who run twin diesel engines (4 motors) with sound and long consists with lights often use 10 amp controllers to give you a clue where you are on the scale of things.



Andrew
 

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For a Porter and powered tender, 1 the 50081 will work for freight. If a lot of lights in cars plus engine smoke it would not be enough.
If indoors with a small layout I would go with 2 amp minimum.
You can use your small power pack with the LGB 5090 plus add a laptop computer supply and get 2.6 amps!! This works for me with the 50081 and the 5090 and a laptop supply for 3 amps.
 

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I think,


by running two locos with significantly dissimilar speeds (i have both) you have, imho, either worn down something in the porter, like an axel gear, which then allows the loco to go out of quarter, or,

By virtue of the porters faster running speed, in essence pulling the tender a bit, ie bigger load, , the porter simply gets out of quarter, possibly due to looser or worn tolerances, in the gears, or the holes/slots for the axels.

Sometimes the gear is very slightly worn, ie a dip in the center of the teeth, and will rin apparently fine, but eventually again slips, usually more quickly with grades, curves, or loads.

Otoh, i understand that some of the later tenders have an internal speed control. If your locos are matched to running speeds, the above may be in part or entirely in error. The older, non german made porters were not as robust and do wear out. If you dont see a gear wear issue, remove the motor and let it run. If it runs erratically, time to replace, if you can.

In reading your info, i understand only the porter pulses and not the tender. If this is correct, then im unsure about the power pack. But, 2 motors is at or beyond the limit for extended running, and would evetually trip the internal circuit protector, as would working the porter harder against the tender, ie slight drag.

The new ones with sound look superb, btw.
 
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