Here are two pictures that show the decoder installation in my RDC.  Both enlarge if you click on them.

 

This shows the whole layout sitting on the installed Lifelike light board.  I disconnected the power to the board and the motor leads from the board and hooked them directly to the two decoders.  This picture also shows one of my pet peeves, HO scale people who don't fit.  The little girl with her teddy bear fits fairly well but the guy sure doesn't.

 

This is a close up of the overall installation.  To the left of the speaker is the DZ143 decoder.  It receives it's power through the two pin connector to the left.  To the right of the speaker is the GE70-2 sound decoder made by Electronik.  It receives power through the two pin connector in the foreground.  I find that programming two decoders in one engine is much easier if either one can be disconnected.  The blue wire in the foreground leads to an LED inside the passenger compartment which is controlled by F1.  Both headlights were also converted to LEDs and are covered with black electrical tape to keep light leakage to a minimum.

 

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