Wiring Ditch Lights To A Soundtraxx MC2H104AT Decoder

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Smudge617

Smudge617

Well-Known Member
I'm replacing the factory fitted plug-and-play light board from an older Athearn Genisis locomotive, because I have several unused and see no point in buying another decoder when I have spares. I've done this before, but my brain is refusing to remember how I did it, so I thought I'd check with you guys.

I want to add ditch lights to a locomotive using this decoder. The basics, how to wire the pickups and motor, I know that, but the ditch lights, I'm not 100% sure, as it's been quite a while since I did this. I also need them to flash as well.

I'm thinking it should be wired one ditch light to F5 and the other to F6, on the decoder, and power is from +U, is that correct ?

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Smudge617 said:
I couldn't find any either, and why F5 & F6. I'll have to try, hopefully without blowing the ditch lights.
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They are separate function outputs. You only need to use one of them for the ditch lights, unless you’re going to have alternating ditch lights.
 
bnsf971 said:
They are separate function outputs. You only need to use one of them for the ditch lights, unless you’re going to have alternating ditch lights.
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Hi Terry.

After having another ferkel around with this locomotive, it seems all the lights are incandescent. But now I'm just confused. I traced the ditch light wiring back to the factory-fitted board. Each light is connected to these two terminals, but both wires from the same ditch light go to the same tab, there's no return or common, so how do they even work, I always thought you needed to make a circuit ?
Sorry electrickery was never a strong subject for me, it's probably a dumb question.

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So, if my thinking is correct, as these are incandescent, it doesn't matter which of the four wires I connect to the +U on the headlight tab, (with resistor, although I think the a MC2H104AT has them already fitted) and the second wire from the ditch light, I can either connect both wires to F5/F6, if I want non alternating ditch lights or connect one wire to F5 and the other to F6 for alternating lights. Have I got that right ?

I honestly have no idea why this is becoming so difficult. I should know by now how to do this, I think my brains going, no idea where, but certainly nowhere I can find it. :D
 
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If you look closely, the factory board has F1N and F1P, so those are providing the power and ground. The soundtraxx is not built that way.

I found this but what he says about reading the pos voltage on F5 doesn't seem right. But he's reading over 12vdc.

LED Resistor - STUMPED | The Atlas Rescue Forum

Hello all, Trying to add Ditch lights to an Athearn BB GP50. I am using prewired 0402 WW in DW castings. I have the LED's set up in parallel. The decoder is a Soundtraxx MC2H104AT board. Now co
atlasrescueforum.proboards.com atlasrescueforum.proboards.com
 
Oh yeah, forgot to mention that the athearn incandescents are 1.5v, so they are very easy to blow. I didn't know that as I blew mine up after I had glued them in. And yes, no polarity on incandescents.
 


Does that 8 pin connector on the factory board have the female sockets? Looks like it does not.
 
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