There's not much room inside the Atlas RS-1 and I originally just used a LokPilot decoder to get DCC in it. However after some time and the introduction of the LokSound Nano decoder, I decided to see if I could get sound into my RS-1 as well. I didn't take many photos along the way but I think most will be able to follow along. However this is not a good choice for the first time installer.
The decoder will sit in the long hood side of the locomotive and the frame needs to be milled in this area. It's hard to describe what needs to be removed and hopefully the photo helps. Remove the shrink wrap from the decoder and then remove the unnecessary function wires keeping only the white and yellow function wires. The decoder will be placed component side down and the wired side will face up. I rearranged the remaining wires so they don't cross over each other which adds unnecessary height in the decoder area. It's a tight fit and every bit of space is needed. Also be sure to add some kapton tape either on the frame or to the underside of the decoder to prevent shorts.
The speaker is located in the short hood area and the frame needs to be milled to accommodate it. It is a 8x12 Soberton speaker from Digikey with a 3D printed enclosure from Shapeways. These both have to be modified. I sanded the bottom of the speaker enclosure until it was almost paper thin. I think I sanded the side slightly as well so it would slide under the shell easily. The speaker was placed face down in the enclosure but I filed some material off the corners of the speaker where it catches the inside shelf in the speaker box. This allows the speaker to sit slightly lower in the box. Also seen in the photo is the original light board that was cut short and used to attach the red and black wires from the decoder.
Keep all the wires as short as possible and tape them flat on top of the frame so they don't climb on top of each other. There is no room inside the shell for a keep alive cap but that didn't stop me. I cut a hole in the hood where the cab attaches. This allows the 330 microfarad cap to stick up through the shell yet be covered by the cab of the locomotive. The black shrink wrap is covering the resistor for the short hood headlight. I had to mill part of the frame so it would sit low enough for the shell to fit. In retrospect I would probably try to place it directly under the LED which is glued to the end of the speaker. The long hood headlight resistor is resting on the decoder board as there is room away from the attached wires of the decoder.
I also noticed there is space to add some weight to the inside lower half of both sides of the cab. This final photo shows the weight I added along with the keep alive cap sticking out of the top of the hood before I placed the cab back on the shell.
Finally here is a short video after I buttoned it back up. The video was taken before I replaced the couplers with Z scale #905's and also weathered the unit.
