This process should work for most Athern engines. I have GP9s', an SD7, and a SW1200 and they all look like the process would be the same. If you don't have the April 1997 issue of Model Railroader, you might want to get one. Keith Gutierrez and Lee Rayburn have written an excellent article on Decoder installation and the drawing of a typical Athern installation really puts all of this in context. (Thanks guys.) If you don't have the April MR then read on.
First, remove the shell. If this is a new stock Athern, you'll notice two things right away; First there is a silver bar connecting the rear truck pickup to the front truck pickup using spring pressure and second, there is no bulb or way to mount a bulb in the back. Now you know why the rear light was always so dim.
Also, if you were like me, when you first put the engine together, you skipped over doing something about the front cab number plates because of the way the little triangular piece of clear plastic (lucite?) was installed. Well, I figured I would do something about that little oversight this time around. I also figured that the engine was way to light. I am adding another page to this site listing what I did and didn't do and why. Check back in late April 1997. Now back to the Lenz install;
Let's first decide where we are going to mount the decoder.
While this engine has plenty of room, there is nothing to mount the decoder on. After much
thought, which included at least 4 bad ideas, I decided to mount it on top of the motor
with double stick tape. Actually I have half of the decoder sticking out into space
over the back of the motor. I have an undue fear of shorting out one of these
expensive little toys and knowing that I would have to solder a wire to the center of the
top motor clip and determing that the bottom of the Lenz decoder is insulated by a thin
coating of some sort I imagined vibration eventually rubbing through and shorting.
Might just be a lttle paranoid. Anyway that's where I put it and it worked out when
it came time to install a rear bulb.
The motors mounts will unseat and the motor will pull free
from the frame. Remove the motor mounts and set aside. If you look on the bottom of the
motor you will see a brass retaining clip. Gently pop this off, BEING CAREFUL NOT TO HAVE
THE BRUSH SPRING fly across the room. Now, if you look at the retaining clip you will
notice two little tabs in the center that actually press down against the frame to
complete the motors electrical circuit. Clip these off and file the area smooth. You will
want to solder the GRAY wire from the decoder to the clip. Temporarily, lay the decoder on
top of the motor, measure off enough of the gray wire to run forward to the front of the
motor and then down the side of the motor to the bottom front where the retaining clip
will go. Cut to length and solder it to the front of the clip in the little indentation so
that the wire feeds out from the clip horizontal to the frame when the motor is in place.
Since the motor can rock back and forth on its mounts, you must ensure that the area beneath the motor is electrically insulated. If you have nylon packing tape, you can cut it and put in the motor well, making sure you leave the holes uncovered. Use two layers. I didn't have any nylon reinforced tape around, (do not use black electrical tape, it gets hot and rolls up) so I cut a thin piece of styrene to fit and glued it in with Goo.
Replace the motor mounts, reconnect the front universal joint, press the front motor mounts gently into there holes, now try (about 200 times) to reconnect the rear universal joint, and then press the motor into the frame firmly. Cut the orange wire to approx. 2 inches in length and solder to the center of the top retaining clip. I did this without removing the clip by putting heat sinks at both ends of the clip and soldering very fast.
Mount the decoder
Put a 3/8 inch piece of double stick tape on the top of the rear portion of the motor. Press the decoder onto this tape with about half of it sticking out into space toward the rear of the engine.
Jumper wires
Take a piece of stranded, reasonably flexible, 22 AWG wire and solder one end to the rear truck pickup tab, the silver thing sticking up, and the other end to the front truck pickup tab, (not the front headlight mounting bracket). If the wire is to stiff the trucks will not have the freedom to turn and you will derail on every number 4 switch you have. I decided to leave the front headlight mount installed. This turned out to be a good idea. Solder the black decoder wire to the front headlight bracket. Now would be good time to test what we have done. Roll up the remaining wires out of the way and put the engine on your programming track. It dosn't work does it! Heres why, only worried me for a few hours....Even though CV29 had a 0 there is a caveat on page 60 of the DCS100 User manual; "If you have a decoder that does not understand Advanced 28/128 speed step mode, you will need to status edit that locomotive to Standard 14 speed step mode". Grab your manual, go to page 60, after you get that figured out and the engine runs, come back to here.
Welcome back, lets wire the lights, or you can send me your questions or you can talk to your local hobby shop guy.
First, do you have some 1/16" heat shring tubing? If not, don't go any further until you get to Radio Shack. I use 12 volt, 50 ma bulbs that I get at my favorite Hoby Shop. Lay one of the bulbs on top of the front (only) headlight bracket and run the two wires back through the hole in the bracket. Use, my favorite, double stick tape to hold the light in place. Put the tape about 1/4' behind the bulb. Take the white decoder wire, pull it toward the headlight bracket, cut the wire just before you reach the front light bracket. Cut one of the headlight wires so that you can connect it to the white wire. Take a piece of shrink tubing, place it over the white wire, now solder the white wire to the headlight wire, pull the shrink tubing over the bare wires and heat with your soldering iron. Now, cut a piece of double stick tape equal to the size of the decoder that is hanging out into space. Take your second bulb and position it so that it is about 1/4" from where the shell would be if it were in place and then use the double stick tape to STICK these two wires to the bottom of the decoder. With a little luck, and stiff wires on the bulb, it should be sticking out and pointing towards the rear headlight lenses. I pulled one wire around the left side of the motor and one wire around the right side of the motor. The yellow decoder wire goes to one of the rear bulb wires, measure twice, or three or four times, cut the wires, slide on the shrink tubing, solder the wire, shrink the tubing over the connection. The last connection is to take the remaining two bulb wires and the blue decoder wire a and solder these together. Back to the programming track and using your Function keys, make sure F0 is set to on. Now, put the engine on the track and test that the lights are directional by pressing your directional arrow key. Well that's it. I am going to work on a speed table for this engine. Doubt that I'll ever doublehead it with thePrtoto 2000 GP18 but I think I can get it close.