Parts Required:

1 x Digitrax DN163A0 decoder
1 x Atlas H-15-44 or H-16-44 Locomotive (The only difference between these models is shell detailing)
2 x SMD LEDs
2 x Resistors to suit LEDs
1 x Sheet of 0.5mm sheet styrene
Thin electrical wire (can be left over from previous decoder installs)

Tools Required:

Needlenose Tweezers
Needlenose Pliers
Soldering iron & solder
Jeweller's screwdrivers
Electrical tape
Hobby Knife

Instructions:

Part 1: Hardware

1) Remove the frame from the mechanism by pulling the shell up and off.

2) Remove the trucks and fuel tank, then undo the two screws holding the mechanism together - one at each end. Undo the motor clips, then remove the light board.

3) Remove the two black clips, then cut two rectangles out of styrene stip to fit in the slots beneath the black clips at each end of the loco. Note that the gap at one end is narrower than at the other.

4) Solder the positive terminal of one of the SMD LEDs to the lead of one of the resistors, as close to the body of the resistor as possible. Solder a length of wire to the other end - about 1/2 inch for the wider end, and 2 inches for the narrower end. Glue the LEDs onto the styrene rectangles, and use the electrical tape to isolate the connections to the LEDs:



Solder another length of wire to the other side of the resistor, as close to the body of the resistor as possible, and the same lengths as above.

5) Cut two lengths of wire, both 1/2 inch long. This will be the common return wire. It will need to be soldered to one of the pads near the LED on the end furthest away from the motor contacts. Solder the two wires together, but don't mask off the connection just yet. Solder one end of the wire to the pad on the decoder board shown below:

6) Put a piece of electrical tape over the motor contacts, just leaving the tops free. Then insert the two LED assemblies. Feed the wires from the LED assemblies through the holes in the decoder board while inserting it where the light board was, making sure that the motor contact pads are on the bottom and over the motor contacts:

7) Trim and connect the positive wires from the LEDs to the positive wire from the board - the one coming through the middle of the board to the middle of the wire, and the one on the end to the end of the wire. Use electical tape to isolate the two connections.

8) You will need to modify the black clips to accomodate the new LEDs. Trim the gap at the bottom of both so that it clears the LEDs:



Then re-insert the two black clips.

9) The negative wires will need to be connected to two more pads on the decoder board. The wire from the broad end (purple in below photo) goes to the pad nearest the end, and the other wire goes to the next one down. These pads are located on the end of the decoder closest to the motor contacts:

10) Re-assemble the locomotive, then test on a programming track. One you have verified everything is working, it's time to move onto programming.

Part 2: Programming

With this installation, the LEDs mounted on the decoder board illuminate the classification lights at the corners of the locomotive, and the extra LEDs provide the headlights. So there will need to be some function remapping done:

CV	Value	Role
33	8	Maps function pad 4 to F0F (Forward)
34	4	Maps function pad 3 to F0R (headlight reverse)
35	3	Maps front & rear board LEDs to function 1
49 & 50	0	Sets board LEDs to non-directional on/off
51	34	Sets function 1 output to non-directional Mars light. Directional lighting is handled by F0F/F0R remapping
52	34	Sets function 2 output to non-directional Mars light. Directional lighting is handled by F0F/F0R remapping

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