Installation of plug and pray decoders in Atlas N scale can be troublesome. The problem lies in the connection of the motor contacts to the decoder.
The engine that runs away at full speed most likely has one or both of the contacts touching the frame. Wrap the frame on both sides with Kapton tape and align the contacts so that they are on the decoder pads. IIRC, NCE has slots so the contacts will come through the board. Make sure they are in the slots if the decoder is so equipped.
The second engine that will not go at all may have poor or no motor contact or as already posted, the board may be sloppy in the two frame mounting slots. Add some solder to the decoder pads to get better contact at the frame. Check the motor contacts so that again they are making good contact with the decoder's pads. As in the first engine wrap the fram on both sides with kapton tape.
Martin Myers
Sometimes you must put a small amount of solder on the four tabs on the decoder that fit into the frame slots.
Most times I find that the board does not make good contact. Also I always solder the two motor leads that fit into the two slots on the decoder.
One other thing?? Did you use Kapton tape on the frame on the left side per the instructions per NCE? It is very easy for the motor lead to touch the frame in some cases. The tape will prevent a short!
skagitrailbird It might help if you specify which locomotives and decoders you are asking about. Also the make and model of DCC system you are using.
It might help if you specify which locomotives and decoders you are asking about. Also the make and model of DCC system you are using.
Try a reset on the decoders to the factory default settings. Then work from there.
Mike Lehman
Urbana, IL
I am struggling to install decoders into my Atlas N engines.One runs away at high speed totally out of control and the other will not move although the lights are controllable. I have spent hours on the installation taking care to align the tabs. I have not had these problems before. Any advice appreciated. Thanks from UK