Fitting a LED to the Austrains 36 headlight.
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Three circuit board pins were inserted into holes I drilled in the tender floor. These pins act as termination points for the headlight wiring. Do your own thing. Connect the decoder’s blue, white and yellow wires to these.
A suitable voltage dropping resistor is wired into the common blue wire. In this case a 10,000 ohm resistor that allows 1.1 mAs in bright and 0.6 mAs in dim. The below photo shows the LED with dim selected. LEDs once illuminated do not have a large variation in brilliance like an incandescent lamp.
The LED orange wire is connected to the other end of the resistor and the black wire to the white function wire, FOF.
Run these wires with the decoder wires to the loco body. This will make 6 wires running from the tender.
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Note: The blue TCS T1 is used for the motor and LED control. The yellow Soundtraxx DSD-100LC is used just for sound that cannot control LEDs, they don’t extinguish when selected off. Along with noisy motor control, this why I use the second decoder.
I use 3mm Prototype White LEDs from DCC Concepts.
LEDs are polarity conscious. The black negative wire from the white decoder wire MUST be connected to the LED cathode lead. This is the lead next to the “flat” on the LED body. The orange to the other.
When the wires are attached to the LED, remove with the Dremmal, the LED shoulder so now it is 3 mm all over.
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Remove the headlight assembly by twisting – be careful.
Drill a 3 mm hole in the boiler where the headlight was.
Install the LED from within the boiler and sticking out as shown.
Drill a 3 mm hole in the rear of the headlight assembly being careful not to damage the lens. Use a few drills to finally get a 3 mm size hole.
Test fit the headlight until both headlight and LED fit tight.
Paint around the LED with black paint so that no light can be seen from the side when the headlight assembly is installed.
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Shape the headlight to give the best fit onto the smoke box door. This maybe best done before the LED is installed.
When all fits well, glue the LED into the smoke box door and the headlight onto the front.
Use a voltage dropping resistor that gives the best “illumination” of the LED that you desire.
This is one of the great benefits of using LEDs instead of incandescent lamps and the LEDs have relatively constant brilliance irrespective of DCC track voltage. See my notes on LEDs for headlights. |
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The final product a LED headlight with DIM selected. Current flowing through LED 0.6 mAs and no blue tinge.
If you cannot get the Prototype White LEDs then use one high intensity white LED that has the lens painted with orange paint. Painting the LED is a little difficult due to the plastic used. I would thoroughly recommend getting the 3 mm from DCC Concepts.
Hopefully your installation will turn out better than this one.
Adding lights is a lot of extra effort but the final result is worth all the effort. You will agree when the loco runs around the layout with lights, you will add LEDs to most of your locos, as I have. |
