This is where I will be posting about how to install a Digitrax DH123D DCC decoder into a(n) Athearn GE C44-9W or Dash 9 Motive Power.
Examen the insides of the engine and decide where the DH123D is going to be installed.
A picture of the engine with the shell on.
The engine with the shell off exposing the simplistic design of the Athearn.
Because space is no issue here I can install the decoder in either the front of the unit or in the rear. I was thinking the front but decided on the rear because of how long the wire harness actually is for the DH123D.
Prepare the chasis of the engine by removing the motor (do this very carefully to avoid damage), the two rubber motor mount grips, the long silver center peice of metal (this can be disregarded if you are installing the decoder the same way I have), and the front headlight mount.
After the engine chasis has been preped you then need to cut bothe the green and violet wires to almost the bare 9 pin harness.
Fourth you will solder the black wire (negative) from the decoder to the rear truck's metal pick up where the long metal clip used to pick up power. I went a little bit further with this install then is needed by soldering a black wire from the rea truck pick up to the front truck pick up to ensure a steady supply of power to the decoder.
To solder the red (positive) wire of the decoder to the rear truck you must take off a few peices of the drive shaft so as to not accidently melt them as you solder the red wire to the center plate of the engine. Note I did not notice this metal peice when I first started the insatllation. Whe I originally started I tried to solder the red wire directly to the chasis where the positive motor pick up used to be but this does not work as the chasis is made of a type of metal that will not hold solder. This metal piece on the truck was hard to discover at first and was only found because I got to thinking how on earth the center part of the chasis was getting positive power and figured it had to be coming from the wheels. As it turned out there was indeed a pick up for the positive side and the metal plate rubs against the chasis suppleing power to the motor. This is probably why some Athearns will stutter when running. you can simply solder a wire from the pick up to the motor for DC versions to help improve on this slight flaw. Note this does not stop power from flowing through the chasis so the motor must still be isolated. You can also do the same with the red wire as I did with the black but I opted not to as I did not have enough wire and this would crowd the engine with the shell on even further.
The first important part of the install is finished.
We now move to the front of the engine where the forward light is housed. This part gets complicated as you should remove the entire light housing from the frame. This includes the brass negative power pick up rod, the silverish metal piece that suplies positive power to the bulb, and the black piece that holds the bulb, silver pick up and the brass power pick up rod.
To remove the silver power pick up you must pry it off. Since you have pried off the power pick up you now need to cut the silver pick up so that only the hollow square is left. You will also have to cut the brass power pick up in about half so that it does not touch the front truck negative pick up. Now that we have all the pieces tooken care of we can begin soldering. You need to solder either the white (forward) or the blue (common) wire from the decoder to the brass power pick up. I chose blue.
Next you will need to solder the white or blue wire from the decoder to the silver pick up square. I chose the white wire but this will have no effect either way.
You can now finally reassemble the front headlight assembly.
Note that there is a round black peice in some Athearns that holds the bulb and acts as a directional piece. Since we have gotten rid of the silver peice that used to support the entire assembly you will need to either try Testors plastic glue, CA, or super glue and glue this piece
to the front headlight lens piece.
You have now completed another important part of the DCC install (the headlights)
I want to add that in some athearn models there can be a reverse light. for this type you will do the same as described only switch out the white for yellow wires from the decoder.
You now need to very very carefully remove the top copper piece that is on the top of the motor. Be carefull as to not go launching the springs from the motor as I have done many a time. Take this piece and solder either the grey (motor positive) or orange (motor negative) wore to this peice. DO NOT REASSEMBLE THE MOTOR AT THIS POINT!
Now carefully turn the motor over being sure not to loose any of the brushes. You now must remove the positive copper motor pick up. This piece has to metal prongs that stick out and would for DC touch the chasis since this is to set it up for DCC/DC operation you must chop these two prongs off. You can then solder the grey or orange wire to this copper piece.
Now we will begin reassembly of the motor. First carefully place a spring (and a brush if you removed these as well or if they fell out) into the Brush holder and replace the copper positive pick up at the same place you removed it from earlier.
Now flip the motor back over and place a spring and any applicable pieces back into the brush holder. Then carefully put the negative pickup back on. (This is the one that did not have the two prongs on it.)
You must now place the two rubber motor mounts you removed earlier onto the motor itself and place the motor back into its original place. I recomend before doing this step to place ideally a pice of electrical tape to where the old positive motor power pick up prongs used to touch but regualar scotch tape works as well. You should not need this but this ensures an isolated motor.
NOTE. Be very care ful when you put the motor bach in place and reconnect the front and rear drive shafts. I broke a peice of the rear shaft while trying to refit it. You may have to take the trucks off to reinstall the motor. Now place the front headlight assembly into the black holder you had glued to the front headlight lens earlier. now carefully plug the decoder into the harness and tuck the loose wires up towards the roof of the shell and reatach the shell.
You Have now finished the wireing of your DC engine to run in DCC, Test it out and have fun.
I have tested mine and everything works fine and even better than it did in DC so this install guide should create no problems with your engine if you have followed all steps acordingly.
This peice can be disregarded or saved for parts for other DC Athearns.
I will eventually be getting the Digitrax DH123AT and will be installing it in yet another even older Athearn and might do a DCC install on it as well.