Athearn BB GP......


WC3026

Member
Finally got a decoder into the used BB i picked up a week ago. test ran it on DC and it ran ok so I did a partial tune up to it. Well now with it on DCC it is slower then you know what. I have my settings maxed as far as I know but still slow. I put the same settings into another BB i have and it took off like a rocket. I did notice that there was some end to end play in the motor but not more then all my other BB locos. Could I have a tiered motor?

the only thing I have not done to it is trimming the brush springs.
 
Finally got a decoder into the used BB i picked up a week ago. test ran it on DC and it ran ok so I did a partial tune up to it. Well now with it on DCC it is slower then you know what. I have my settings maxed as far as I know but still slow. I put the same settings into another BB i have and it took off like a rocket. I did notice that there was some end to end play in the motor but not more then all my other BB locos. Could I have a tiered motor?

the only thing I have not done to it is trimming the brush springs.
Have you put the motor on a meter to see the current draw?
 
Trimming the brush springs may help, but did you have the brushes out? They have to go back in making full contact to be efficient. Rotate 90 degrees and they loose contact. Also did you take the armature out, maybe didn't reinstall the magnets as they were?. After polishing the commutator, did you clean the gaps between the segments??
I'd start there..
 
When I cleaned the commutator I did clean out the gaps when I was done. I never took the bushes out so that is not an issue. I have it running right now thinking that maybe the more I run it the better it will get it seemed to speed up a bit but not like it should with the settings I have it at.


I just took a better look into it and noticed that whn I give it power it makes a higher pitch noise while waiting for the motor to start turning. Even when the motor is turning it still makes a higher pitched noise.
 
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I just took a better look into it and noticed that whn I give it power it makes a higher pitch noise while waiting for the motor to start turning. Even when the motor is turning it still makes a higher pitched noise.

That may not be the motors fault, maybe too much PWM (pulse width modulation). You stated you had jacked up some settings, I suggest to do a reset on the decoder to factory settings, and see if the noise disappears. Then go from there.
 
I am thinking I got a bad decoder I took one out of my Athearn RTR, put the one I had in the troubled engine into it and it did the same noise. I did reset it to factory settings. I tehn took the decoder from the RTR and put it in the BB, It ran great. guess digitraxx will be getting one sent back to them.
 



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