athearn sd40-2

Model Railroader Electronics and DCC
1

i added a digitrax dh123at to my athearn ready to run sd40-2 and the top hatch does not fit right. i think i fried it on the reverse curve other post. any way now i got a dh 123 d in there. is this a good fit or are there any n scale decoders that would fit better?i read about another poster said he had to much heat build up because the hatch would not go back on. thanks to any one who answers.

2

Did you isolate the bottom of the motor?

The DH123AT is why I suggest that people learn how to properly harwire a decoder into place.

David B

3

no sir i did not i just took the dc plug out and added the dcc plug from the decoder in. thought that was all i had to do.

4

I am confused here sir. You mention Athearn SD40-2. Now, this comes in 2 flavors, RTR and Blue Box. You also mentioned DH123AT which is a hardwire solution for the Blue Box series of locomotives, so I assumed you have a Blue Box. You last post mentioned that you removed a DC plug and plugged in the DCC decoder, so I have to assume you have an RTR model.

So, which is it? Do you have an RTR model or a Blue Blox?

David B

5

sorry for the confusion. if you read my first post it says ready to run sd40-2 .might have mislead you but not a blue box . i have a lot of blue boxes i would like to convert but my question was about the hatch not fitting right after i put in the digitrax decoder. and is there a n scale decoder that would fit? thanks again.

6

I don’t know about any N Scale decoders but I know for a fact that the Digitrax DZ125 Z Scale decoder will work in it and it will fit almost anywhere. I’ve put them in all kinds of Athearn locos from switchers on up to an emmense SDP40F with one of those being an SD40. The DZ125’s current rating is 1 amp, 1.25 amps peak. I haven’t had one burn out yet.

7

what is the price of a z scale decoder? 25 .00 for ho .

8

$24.99 from Walther’s.

DZ125

9

Now you got me worrying, I just bought an Athearn RTR High nose NS SD40-2 and was expecting to fit either a Digitrax DH123D or NCE D13SRJ or TCS T1. Which one do you suggest for that engine?

10

Don’t the Athearn SD40-2’s (and several other Athearn SD/GP models) have a weight pocket built into the shell under the dynamic hatch?

You could either carve it out, since it’s probably not adding enough weight to make much difference, or you can look for an extended JST harness that lets you put the decoder into that pocket, in place of the weight.

HTH,
Steve

11

Thank for the tip, this is my first Athearn RTR and I did not open the shell yet, I will do and see.

12

I should have removed the shell and take a look before asking the question. While there is no weight pocket under the dynamic hatch, there is ample space, after removing the dummy GST plug, to fit either a Digitrax DN143IP or NCE N14IP.

13

Is there an 8 pin socket? I have hit or miss…some Athearn boards had the 8 pin holes, but no socket…which means you have to solder the pins to the Athearn board. If it have a socket, you are golden. Always remember to remove the 9 pin JST dummy plug, or you will fry your decoder.

David B

14

Yes it does have the 8 pin sockets no soldering required.

I have a Genesis with this board where there are the 8 holes but no socket, a 9pin GST decoder was installed int that engine.

Thanks David

15

JST…JST…we dont tax our sockets…[xx(]

David B

16

Thanks for the correction David. Here in Quebec we are so heavily taxed, I guess it show in my writing.