I"m putting an N scale sound decoder in my Bachmann GP38. I've got the decoder hooked up and it's moving and making sound, but I haven't yet re-attached the lights. (the wires on the decoder harness are too short to reach to where the lights need to be, but that's another story). I've got some questions regarding this. 1. If I want to use LEDs (which I are brighter, right?) do I need to put a resistor (or is it a capacitor?) between the power source and the light? 2. The wiring diagram I have shows a white ( - ) wire and a blue (+) wire going to the front light. Does it matter which wire goes on which "prong" of the light? Also, the diagram shows a yellow (-) wire and the same blue (+) wire going to the rear light. I guess this means that the blue wire has to have a "three way" connection? Any tips on how to do this neatly? Thank you.
I just did Tsunamis in a couple of my N scale steamers and changed the LED's. You need a resistor on the white wire. I used 680 ohm resistors and sunny white LED's and they look good. The blue wire would be a 3 way connection. Yes it does matter what wire goes to what leg of the LED. The good news is, if it doesn't work the first time around, just switch the wires. More here: http://www.kpsec.freeuk.com/components/led.htm
