Model Railroading > Atlas GP40 & C30-7 DCC and detail questions

The first picture shows an Atlas GP40 from, I think, the early 2000's. Unlike newer engines it doesn't have the orange/black engine wires. Instead, the lights and trucks are all black wires, and the engine wires are red/black. Once I get a decoded I'm unsure what wire goes where in that case. Second, I've searched about DCC for these engines alot on here but couldn't find a clear answer on what decoder (non-sound) might fit or be best for this engine. Does anyone know?

Second - I plan to paint this engine in the CSX boxcar scheme as a fictional rebuilt that gives me an excuse to have a GE FDL-16 chugging away on my layout. Is a Tsunami TSU-1000 FDL-16 decoder the best choice for sound in this engine?

I'm also trying to figure out what details to add. I'd like to replace the radiator with etched metal/see through grills. Looking on the Atlas parts website I might be able to use a B23-7 shell or that, but I haven't found any other option. I'm also looking for modern cab mounted A/C units but haven't found any. Ditchlights I've got covered... are there any other details to recommend for a C30-7?

Thanks in advance for any advice.

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For the decoder, a nice drop-in for this locomotive is the NCE DA-SR. It will clip to the top of the motor nicely.

As for the wiring....if you use a DA-SR decoder the wiring will become super easy to see. The wires from the trucks will almost automatically align with where they go on the board. Basically the outer posts on each end of the decoder are the track pick-ups.

The red wire on the motor is motor positive (red = positive) and black wire is the motor negative (black = negative). These will go to the two posts on the edge of the DA-SR.

The lighting goes in the center two posts on the ends of the decoder. Note that one post is marked with a "C". This is the common for the (+) side of an LED. The (-) side of the LED goes to the post with the output number (1 for the front and 2 for the rear). You can tell the (-) leg of an LED by looking inside the globe for the triangle "flag" or the flat spot on the globe base. A nice feature of the DA-SR is that it has built in 1k ohm resistors for LED use. All you need to do is cut the trace bridge around the appropriate resistor for the lighting output to activate the resistor. The DA-SR instructions show you how to do this.

DA-SR: http://ncedcc.com/component/virtuemart/?page=shop.product_details&flypage=flypage.tpl&product_id=47&category_id=13

Lee Ryan - Rio Grande Fan
Denver, CO



Edited 1 time(s). Last edit at 01/31/14 09:41 by RioGrandeFan.

Thanks, that is very helpful.

There are several vendors that make "Atlas" style decoder boards. NCE is a good one but Digitrax makes them and Soundtraxx makes them in sound and non-sound versions. I'm probably missing other options. The instructions on any of these should make wiring fairly straight forward.
For my BN C30-7s a front anti-climber was something I added. I think Details West and High Tech Details both make them. I see High Tech Details also have C30-7 radiator screens although I haven't tried them.

Stephen

Consider using double-back adhesive foam tape to hold the board in place. Either stick it to the weights or the top of motor. The underside of the decoder board typically does not have any components so it should not be a problem with heat dissipation, of course some amount of consideration is required. You can also put two pieces together to build up a little height.