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Hard Wiring a Decoder to a DCC Ready Locomotive

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  • Member since
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  • From: Dearborn Station
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Hard Wiring a Decoder to a DCC Ready Locomotive
Posted by richhotrain on Thursday, May 1, 2014 11:45 AM

If you need to hard wire a decoder to a DCC Ready locomotive, do you remove the DC circuit board and simply connect the wires from the decoder harness to the appropriate wires on the locomotive chassis?

Rich

Alton Junction

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  • From: Phoenix, AZ
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Posted by woodone on Thursday, May 1, 2014 12:25 PM

What scale? What locomotive?

Need more information for me to help.

 

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Posted by mlehman on Thursday, May 1, 2014 12:50 PM

If you want it hardwired, in most cases you can cut the wires and simply resolder to the appropriate leads on the loco. This presumes the original DC board had a harness connecting it to the loco, as many do.

There are some locos where the board is in tight quarters and the DC board simply make contact with all or part of the motor, lights, etc by sitting or plugging directly into a mount on the chassis. Then you'll have to devise ways to attach wiring to connect your new DCC board, although I've seen cases where a plug was also provided so it could still be plug and play if the DC board is retained. A lot of Athearns are that way, for instance.

Now, if the question really is "Does DCC-Ready ALWAYS mean you'll have wire leads to solder to?" the answer is no, it depends. "DCC-Ready" is more a concept than it is a specification of what to expect.

Mike Lehman

Urbana, IL

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Posted by richhotrain on Thursday, May 1, 2014 2:17 PM

The loco in question is a Proto 2000 PA, DCC Ready.  The PC board accepts an 8-pin connector.

I have a spare plug-in decoder but the 8-pin connector is damaged.  So, I am considering hard wiring it.

Rich

Alton Junction

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  • From: Reading, PA
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Posted by rrinker on Thursday, May 1, 2014 3:26 PM

 Yes. Pull off the plastic caps, remove the wires, unscrew th factory board. Splice wires to the appropriate decoder wires. It's pretty easy to tell which is which by seeing where the lead to. If this is one with the Mars light, replace headlight and mars light with an LED and 1K resistor, the decoder will do a better Mars light simulator than the circuit on that factory board and th dual-filament light bulb they used. There's actuall plenty of room to just leave the non-disconencted factory board in place and tape the decoder to it. If you ever need o convert it back, you can just clip the wires and reattach them to the factory board, instantly back to original DC loco.

                    --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
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  • From: Dearborn Station
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Posted by richhotrain on Thursday, May 1, 2014 5:17 PM

Randy, thanks for all of that info.   Plenty of food for thought.  I just may follow your suggestions to the letter including the LEDs.  Thanks again.

Rich

P.S. One follow up question.  If you use LEDs but bypass the circuit board, how do you simulate the Mars light?

P.S.S.  When you hard wire, what do you use to connect the decoder wires to the loco wires.  Space will be at a premium so I would need some kind of small connectors that don't take up a lot of space.

Alton Junction

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Posted by mlehman on Thursday, May 1, 2014 6:19 PM

Rich,

Randy's got it covered.

For the LED Mars light with NCE decoders, nothing special with the wiring. I wire mine to Output 3 and map it to Function 1. Then you follow that with setting CV 122 to either 136 (for manual on-off with F1 or whatever you assign it to) or to 137 (if you want it on all the time the unit is in forward.) The decoder generates the appearance of the Mars light. There are a couple of other signal beacon lights you can also try if the Masr light doesn't work for you in terms of appearance.

Mike Lehman

Urbana, IL

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Posted by locoi1sa on Thursday, May 1, 2014 6:46 PM

richhotrain
P.S.S. When you hard wire, what do you use to connect the decoder wires to the loco wires. Space will be at a premium so I would need some kind of small connectors that don't take up a lot of space.

  Solder and shrink tube. You can't get much smaller than that. If the decoder wires are long enough then forget the splice and go right to the trucks, lights and motor.

          Pete

 I pray every day I break even, Cause I can really use the money!

 I started with nothing and still have most of it left!

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Posted by mlehman on Thursday, May 1, 2014 9:05 PM

To elaborate on Pete's post, don't use connectors, solder and shrink instead. Connectors are bulky and tend to fail much more often than a soldered connection will. I bought several packs of connectors from Soundtraxx when I first started converting to DCC. never found a place where I reaslly needed one, so I still haven't opened any of the packs.

In many cases, it's not even necessary to actually shrink the tube. I can tell be the way it's positioned that it's not going anywhere, so I've taken to leaving many of these loose. That way they both insulate and are easy to slide back and put the tip of the soldering iron on the soldered joint to loosen it. That way I don't have to cut anything later if I need to make changes.

Mike Lehman

Urbana, IL

  • Member since
    February 2002
  • From: Reading, PA
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Posted by rrinker on Thursday, May 1, 2014 9:20 PM

 When i did one, I just cut the decoder wires off short, stripped the ends, slid on a short piece of shring tube (don;t forget this step!), twisted the stripped end with the approriate wire I took off the factory board, soldered, then covered the joint with the shrink tube.The one I did didn;t have a Mars light, so I just replaced the headlight with an LED. If it had the mars light I would have used another LED. The decoders I use all have a 9 pin plug (or a smaller one - I used an MC2 in my 44 tonner, a T1 is too big for those), so I can remove the decoder and swap it if needed, and like I mentioned, there is enough slack in the factory wires that if I ever needed to return the loco to factory condition it would be an easy matter to cut the wires and reattach them to the factory board.

 The blue and white wires on the decoder will probbaly not be long enough to read from the back to the front of that loco, so you'll have to splice in some extra wire.

                           --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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