So I detailed and painted up my first Coal Belt loco and I am all done with it except for the headlamps and the ditch lights. I am using those tiny surface mount Richmond Controls leds for each lamp, a total of 8. The leds are wired in series with a 1/2 watt 470 ohm resistor on the positive lead. The Digitrax 123 decoder i had previously installed into the loco while still in factor paint was programmed to control lighting functions with f1 and f3 only. In other words the lamps worked regardless of locomotive direction and only off of function commands. I havent changed a thing on the decoder since I first programmed it and now when i tested the forward leds in the aforementioned setup the leds are on all the time and really dim in reverse. They dont respond to function commands. Do I just need a different decoder with more lighting functions and wire the lamps directly to the decoder, one wire to the common and one wire to the decoder? Just ignore the light leads from the stock atlas board? This proplem has me puzzled
Don
If all you have is head and tail lights than a 2 function decoder is all that is needed. If you want ditch lights on the front only than a 4 function decoder is necessary. Having 8 different LEDs may require a function only decoder and a 4 function motor decoder. 6 function decoders is the most I know of. I have found that lighting and loco performance is better hooked directly to the decoders. I always scrap the factory boards and hard wire either a decoder harness with 7 or 9 pin JST connector or the Atlas style board replacement decoder in with LEDs and 1/4 watt 1K resistors.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
Have you checked CV 49 and 50?? On most decoders you can use those to set up the headlights so that they're bright in the direction of travel, but dim when in reverse (the way I like to set my engines up by the way). Worth looking at. It could be there always was a little power going to the old headlights, but not enough to be noticeable. LEDs need very little power to glow a bit.