I have a Athearn “Blue Box” GP 35 that I have resurrected from a non running unit. I cleaned it up, replaced all of the lube & got it running good, but it is slow. It sounds good, nice & smooth, keeps a nice even speed but it runs about half the speed of my other locomotives. Any idea on what might cause this?
Could just be a weak motor. Have you put a meter on it to determine the current draw?
Could be the gearing. What other locomotives are you comparing it to?
I’m comparing it to other athearns from the same era. I don’t have a meter so I was unable to check it but I can bring one home from work (if I ever get back there)
Micheal, more than likely a bad motor, but how old is the motor or should I say what does it look like? When I got stated I bought a lot of old BB engines. Some had what was called Rocket Motors, should have been called Rock Motors. They where some what rounded looking and gray in color. When I bought a few I was running a MRC 1300 and two could barely move. Heck one would hardly move!
Then a bought a MRC 9500 and I could run them. They are long gone now after I went DCC, each motor would pull around 2 amps.
If the motors are square and gold in color, have you tried replacing the brushes?
Might want to read this.
http://www.mcor-nmra.org/Publications/Articles/Athearn_TuneUp.html
Good Luck, Cuda Ken
Thanks for the link, that should prove to be most helpful as I have an entire fleet of Athearn locomotives.
One way is to substitute a motor from a good Athearn into this chassis.
If the motor is a fault, make sure the shaft bearings are oiled. The armature and brushes can be cleaned if necessary.
If all this checks out, the pole windings may be shorted. This causes the magnetic fields to be less powerful, top speed is reduced and current goes up.
Well, I took the motor out and cleaned up the armature & bushings and that made a world of difference. It was like night & day how well the motor ran. Unfortunately when I took the motor out, the mounts were so brittle that they fell apart in my hands so I’ll have to either get some from a donor locomotive or order some new ones.
Pretty common for them to dry up. Glad the motor runs better now.
Here is the older BB W/ outside bearing trucks.
http://www.hoseeker.net/assemblyexplosionAthearn/athearngp351973.jpg
This is the newer BB W/ inside bearing trucks.
http://www.hoseeker.net/assemblyexplosionAthearn/Assembly%20Explosion%20Athearn%20GP35%201997.jpg
Google the P/N, lots of choices. Ebay might have the best deals.
I never liked those motor mounts. I use silicone to hold the motor on place, but then I have to put in ground screw into the frame and connect the bottom clip.
Mike
I’m not excited about the motor mounts either but I don’t like the idea of gluing the motor in place in case I have to take it out for some reason.
I’ve been learning alot about these old locos as I purchased a large lot of them from someone that thought they were all junk. Several of them have the metal side frames…are they still considered “blue box”?
Yes. That references an earlier era of production. I dont mind the metal frames at all; on the 4-axle units I believe I prefer them! Many dislike the “Jet” motors. If you have a hearty enough power supply and are going DC, I think they sound better than other motors. If you need to watch current draw, replace them with mashima or somthing nice.
Mike
Motors shouldn’t have to come out often. If you try the silicone, you’ll never go back. Make sure to line up the motor with the rest of the drive line properly or you’ll end up with some sketchy operation.
MS
I don’t mind the metal frames either, I must admit though that I was a little confused at first as to how the power was transmitted to the motor as I had never seen one like that before. It also took me a little while to get all of the crud out of the sideframes so that it would work properly.