Installing DCC into old Athearns?

Model Railroader General Discussion (Model Railroader)
1

If anyone knows of a web link for “Installing DCC” into older Athearns could you post it on a reply.
Thanks,
Brad

2

You can use this particular Digitrax DCC decoder, which has the clips that fits onto the old blue-box Athearn locos’ motor contacts: http://www.digitrax.com/prd_mobdec_dh123at.php

It’s supposed to be a solder-free install (check the instructions at that page I linked to). Sounds easy enough.

Hope this helps!

3

Brad I just converted an old Athearn BB F7A from 1984. I used the decoder that Tom mentioned. Except I used the DH163AT (rather than the 123) because it has some extra func wires. It is a solderless installation. It comes with great instructions. Basically you remove the shell, the trucks and the motor. The motor has two brass clips that hold it together and provide power. You replace the two clips with the clips (with wires attached) on the decoder. Slide the Right and left rail clips on the trucks and clip on the light and you are ready to DCC. Can’t get any easier. Let me know if you have any specific questions.
Terry
[8D]

4

Tom & Terry,
Thanks about the Digitrax info. I totally forgot about Digitrax as I am going to hardwire these direct using TCS decoders, but maybe the Digitrax instructions will show the wiring layout.
Thanks,
Brad

5

You can also buy the harness alone from Digitrax and use it with TCS or any decoder that has the 9-pin JST plug on it.
The key is isolating the motor - underneath the motor the brush clip has a small tab on it which contacts the frame under the motor. This tab must be cut off and the bottom of the motor cavity insulated so no contact can occur. The black decoder wire needs to contact the frame - this can be doneby drillign and tappign a hole and using a brass screw, and soldering the wire to that. Or even better, solder a piece of fine wire to the side plate of each truck and use that to power the decoder - it will provide a more reliable power pickup that the center pin of the truck to the frame.
As for the light bulb - you’ll probably want to remove that and install proper bulbs or LEDs so they light up the headlight and not the entire cab interior.

–Randy