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Lou's Atlas Decoder Installs

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  • Lou's Atlas Decoder Installs

    Atlas' diesels, except for their S series switchers, accept the Atlas Dual Mode decoder. The decoder can be retrofit to these locos by removing the existing lightboard (which is a motor mounted pc board with 10 connection tabs) and installing the Atlas Dual Mode decoder in the lightboard's place. Wire connections are the same for both devices which should make it very easy to do.

    But, what do you do if you want advanced features like back-emf load compensation and FX lighting with Mars and ditch lights for example. The Atlas Dual Mode decoders don't have that kind of capability. Here's a brief synopsis of what I do.

    In all GP30/40 series diesels with or without the Atlas Dual Mode decoder from the factory, I replace the Dual Mode decoder with the RS11 lightboard, part #850120, which has a dcc socket on it. Then, I simply plug in my choice of advanced feature decoder, usually a Digitrax DH142PS which has a plug on a short harness. In the RS11, I do the same except it already has the correct lightboard with the dcc socket.

    Now the fly in the ointment. With the popular Atlas RS1, RS3, RSD4/5, there's no dcc socket on the lightboard. So, if you want to install a decoder, you have three choices:

    1) Hardwire in a decoder. Not my choice when there are better ways.

    2) Install an Atlas Dual Mode decoder. Well, it fits until you snap the shell back on. Then, the decoder's dcc/dc plug sticks up too far and the shell doesn't snap all the way down. Or else the pc board gets mushed down and scrapes on the flywheel. If you really want to use the Atlas Dual Mode decoder, desolder the eight socket pins from the decoder board and solder the dcc/dc plug permanently in the dcc position. That solves the excess height problem.

    3) Install an advanced feature decoder. Desolder the eight socket pins from a #850120 RS11 pc board. Cut off the two diodes flush with the top of the pc board. Tape a Digitrax DN142 decoder to the center of the pc board. Trim and solder the decoder's wires into the appropriate now-empty socket holes. You will then have an advanced feature, back-emf load compensated special lighting effect dropin decoder which will be slim enough for the shell to fit back on with no interference.

    Here's a graphic:

    I previously posted a topic for installing a decoder in the Atlas S series switchers. Search back if you want it.

    Good luck.