# NCE D408SR Decoder for lighting?



## dperrott (Aug 12, 2010)

When I purchased my NCE PH10-R Wireless DCC system they threw in a NCE D408SR decoder. The decoder says that it is not warranted for use with USA or Aristocraft engines. 

Can I just use the NCE decoder to control the lights within an engine that has a QSI decoder installed? 

The NCE decoder has many lighting functions (8 function outputs with 15 available lighting effects - MARS, blinking, etc...) that I could use. The decoder is rated to 4 amp continuous with some function outputs rated at 100ma and some up to 1 amp. It also says it can support LED lighting. I am making the assumption that if I don't use the decoder for the motor output, that the decoder would be able to easily handle lighting and possibily smoke.

How do you handle a loco with multiple decoders? Does each decoder then get a separate loco number? Can it be programed as a consist?

Just curious to see if anyone has done this before.

Dan


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## Greg Elmassian (Jan 3, 2008)

You can use it just fine on Aristo, or USAT locos. 

There was a big flap about how much current a loco could draw, and while technically correct, from a practical perspective, you never encounter this on these locos. (NCE wants you to use the D808). The 408 will do an honest day's job. 

By the way, I think if you re-read the NCE stuff, it only point at USAT locos, not Aristo. 

Use it as a motor and light decoder. 

When you ask about smoke, you need to just follow the power capability that you already mentioned. The smoke unit you want to use should be measured for current draw. 

How to handle locos with multiple decoders? There's a couple of ways. (this assumes like one is motor, the other decoder is sound, for example) 

1. Set both decoders to same address, just find a way to isolate them when you want to program them. A simple on/off switch to one of the track pickups is easiest. Some decoders have a "decoder lock" function to make it possible that only one will listen at a time, but it's really too complex and not universal right now. 

2. Set them to separate addresses, and consist them. This can work well, but there are nuances to consisting, that can affect lighting, and this again can get a little complex for a newcomer. 

Regards, Greg


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## Cougar Rock Rail (Jan 2, 2008)

Hi Dan, 

All you need to do is give that decoder the same address as your locomotive and you may have to do some function mapping to make sure there are no function button overlaps with your QSI decoder. 

Keith


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## George Schreyer (Jan 16, 2009)

There are ways to deal with two decoders in parallel without the need for switches. I've done this in HO quite a bit for separate motor and sound decoders. 

BTW, the D408 will work just fine in Aristo locos, even the 4 motor ones. They will also work in USAT locos if you add a 0.5 to 1 ohm resistor in series with the motor output. This cuts the stall current WAY down but doesn't materially impact the top speed. Use at least a 10 watt resistor. 

see links 

http://www.girr.org/girr/lamrs/lamrs.html#dual 

http://www.girr.org/girr/tips/tips8/sd45_tips.html#dcc 

http://www.girr.org/girr/tips/tips11/wheel_pitting.html#gp9


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## Greg Elmassian (Jan 3, 2008)

I like your address trick idea... since I never use short addresses, this is a nice simple idea... 

Greg


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## dperrott (Aug 12, 2010)

Yep - I noticed that it says USA Trains and Charles Ro G Gauge engines. 

I am going to try it in one of my Aristocraft Diesels. Just have to figure out which one.... 

Thanks!


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## George Schreyer (Jan 16, 2009)

Greg, since I wrote that I've standardized on the 2 digit addresses 

motor decoder 3 
sound decoder 4 

that way I can easily remember them.


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## Greg Elmassian (Jan 3, 2008)

Very smart and simple idea George! I'm going to have to quote that on my site! 

Dan, the constant current drain of USAT locos will be fine with that decoder, have installed many of them. Following George's advice will ensure no problems, the USAT motors can draw a lot of current for a short time right at startup, so the resistor limits the maximum current inrush, protecting the decoder. 

My buddy RJ and I did an install with a D408 and a Phoenix 2k2 in an S4, came out nice. 

Regards, Greg


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## dperrott (Aug 12, 2010)

OK - I am not an electronic guru so I need to get an understanding of what George means to add the ".5 to 1 ohm, 10 watt resistor in series". I think I can find the resistor but I don't know what you mean about adding it in series. Can someone explain or show an example photo?


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## Greg Elmassian (Jan 3, 2008)

in series with one motor lead, either one will do... cut one motor lead and put the resistor in there so all the current to the motor has to go through the resistor. 

The meaning of series, one after another... the motor and resistor are in series... 

I think it would not be a bad idea to understand series and parallel circuits if you are trying to wire up a decoder... since you often need a resistor in series with a LED to limit current. 

Try googling "series and parallel explained" 

Regards, Greg


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