# Atlas GP9 not running right



## grashley (Aug 27, 2015)

I recently bought a used Atlas GP9. I do not know the age, but it has Rapido couplers.

When I first put it on the track, it takes fairly high voltage (60%) to "get it started", then runs okay. When I stop it, it will no longer run in either direction. Directional headlights work, so I know it is getting power.


Any suggestions?


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## pmcgurin (Sep 7, 2010)

When this happened to two of my Atlas CN GP9s from about that era, I was told they needed new motors. It seemed cheaper to buy two new ones on ebay and swap their mechanisms into my CN units. I have had little luck replacing motors.


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## rrjim1 (Mar 12, 2015)

I would start with a good cleaning, polish the contacts, and lube. Make sure everything is turning free. If it still has problems, then the motor needs checked out. Could be a gummed up commutator, worn out brushes, or a broken winding.


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## Cycleops (Dec 6, 2014)

Something of that age is likely gummed with with dirt/oil. Just carefully take it apart and clean everything with alcohol.


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## pmcgurin (Sep 7, 2010)

Cycleops said:


> Something of that age is likely gummed with with dirt/oil. Just carefully take it apart and clean everything with alcohol.


Are you recommending taking the mechanism apart?


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## Catweasel (Nov 17, 2015)

If it takes that much power to get moving,it's certainly got a problem. Take it apart carefully, if not sure,take photo's, thoroughly clean with alchohol,lightly lube and reassemble. The commutator should be cleaned with a cotton bud and alchohol. If possible, try running the motor out of the frame with a battery. It should run on as little as 1.5 volt. Had a look on line and it looks like an open frame motor. If it's shot, measure it up for length, width and height and see if Mashima have something in their range. Should be possible to fit one. Probably 1.5 mm shaft which will fit the flywheels.
I've now got a few HO BB Athearns and am converting all of them to run Mashima's with DCC.


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## Cycleops (Dec 6, 2014)

Good advice from Catweasel. Those old N locos never ran very well so remotoring it and cleaning it out as suggested will give you the best hope of getting it to run like a modern one.


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## rrjim1 (Mar 12, 2015)

It all depends what loco you have, a picture would help. If it's a Kato built Atlas loco than it's worth fixing up, (Kato will be on the bottom of the fuel tank), if it's older that I wouldn't bother.


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## grashley (Aug 27, 2015)

It is a Atlas Made in China 1986 Molded in bottom.

I have taken the shell off, and it is an open frame motor.

The motor "looks" clean and turns freely. I will attempt to attach a picture (first time).

Is it worth a simple light lube then test run, or does that just make it harder to clean?

How do you disassemble? How far?

HOW DO I UPLOAD PIX????


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## MRLdave (Nov 1, 2011)

The picture helps............As Catweasel suggested, if you have a 9V battery, you can touch one contact on the battery to the frame (one contact on each side of the center seam).......if the motor spins, then the problem is in the pickup, either the trucks or the contact strips between the trucks and frame. If the motor doesn't spin, then the problem is either the circuit board or motor. Atlas locos are notorious for picking up lint in the trucks......the point of the wheels ride in a metal cup which carries power to the metal contact on top of the truck.....the cups can fill with lint and other crud and prevent good electrical contact. To clean you start by loosening the screws on either end of the frame (you don't need to remove, just loosen) which should let you pull the trucks out of the frame. There are 4 little tabs on the bottom of the truck assembly that you need to disengage, which will let the bottom and sideframes slide off the gearcase. At that point you should be able to remove the metal contact strips and clean everything. Keeping the strips in place while you reattach the side frames can be difficult.

If the motor doesn't spin with the battery test, then you'll need to split the frame. To do that, completely remove the frame screws and gently pry the frame apart. There are driveshaft/bearing assemblies and 2 frame spacers that will try to fall on the floor so be prepared. At that point you should be able to remove the motor from the frame.......try the battery test again using the motor contacts ......if the motor spins now, the issue is either the circuit board, the contact pads where the motor touches the circuit board, or the contact points where the circuit board clips in the frame. Clean all contact points and reassemble. If the motor doesn't spin out of the frame, or spins poorly, you're looking at a new motor.

This all may sound complicated, but isn't really too bad. Just go slow and watch how everything is positioned as it comes apart (pictures aren't a bad idea to refresh your memory).


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## grashley (Aug 27, 2015)

Thanks Dave

I never thought of a 9V battery power supply. Works like a dream!!

On the track test, because I did not want to take cars off the track, I ran it about 5 ft. Ran fine. Stop. Run reverse. No movement, but directional light works. Run forward, no movement, but directional lights work.

On the bench, I apply battery 2 - 3 sec. runs great. Reverse battery, as above.

I manually turn the motor, then it runs. Stop. Does not run until I manually rotate motor, then it runs great.

I let it run at 9V for 10 - 15 sec. then reverse, and all is good. Run 10 sec, then reverse. All is good.

My theory - There was a "flat" spot on the motor from storage. Running it with no load for a minute, reversing directions appears to have smoothed the flat spot and cleaned the motor contacts.

COMMENTS??

While I have it open, what should I lube - and not lube.? Light oil, I assume.


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## rrjim1 (Mar 12, 2015)

grashley said:


> It is a Atlas Made in China 1986 Molded in bottom.
> 
> I have taken the shell off, and it is an open frame motor.
> 
> ...


Very good loco and worth putting some work and or money into getting it running great. You can also upgrade this loco with the new Atlas scale speed motor if you want real slow scale speed running. There is a video on how to lube locos on one of the other forums, if you do a search you should be able to find it. It is also very easy to upgrade this loco with MT couplers if you wish.


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## DonR (Oct 18, 2012)

Use only plastic friendly lube, gel for the gears, liquid
for the motor bearings.

Don


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## grashley (Aug 27, 2015)

THANKS TO ALL

I watched one of Fifer's U Tube videos on loco maintenance. He talked about breaking in new locos, especially Atlas and Bachmann. I did the break in run on the loco, and I think that took care of the problem!! It appears quite clean so it may have just wanted some run time!!

PROBLEM SOLVED!!


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