hello all i just added a decoder to my engine but the light went out. my question is what size led light i need an do i need a resistor an if so what size or kind thanks
Hi, and welcome aboard.
Is this your first decoder? Your first self-installation? Also, what kind of a decoder is it?
Did the existing bulb burn out, or never come on? If you're new to DCC, you may not know that you have control over the lights, and you can turn them on and off with F0 on your throttle.
Going directly to the LED question, try to get a 3mm or maybe a 5mm "golden white" or "yellow glow" LED. These have a slightly yellow tint to the light, which looks more like a train headlight than a standard blue-white LED. I use a 1K resistor (that's 1000 ohms) for each LED, front and back. There are few decoders with built-in resistors for the light circuit.
It takes an iron man to play with a toy iron horse.
Did you "blow" the light - It sounds like you need to add a resistor. HO or N Scale ? HO scale typically take 3mm replacement LEDs. As mentioned above, everyone's definition of white is different - you may see a blue tint, golden white, etc. Make sure you are connecting the LED properly to the function/common - anode vs cathode.
thanks guys i found the resistors but i can't find the leds ya talking about also which is the anode n which is the cathode n whats the difference thanks
On a LED, the anode is the positive lead, and the cathode is the negative lead. These must be correctly wired, not backwards, to get the LED to work. Most LEDs I use for trains have two leads, one of which is slightly longer than the other. That longer one, by industry practice, is the anode.
Your DCC decoder has a blue, white and yellow wire. The blue wire should be connected to the anode of the headlight. If the engine also has a reverse light, the blue wire should also be connected to the anode of the LED you put there.
The front headlight should be connected to a resistor, and the other side of the resistor is connected to the white wire. Similarly, the rear light should go through a resistor to the yellow wire. If you use any of the "lighting rules" where both headlights might be on at once, the use of two resistors protects the resistors from overheating. Alternately, you can use a single, higher wattage resistor (that's wattage, not resistance) on the blue wire, and connect the resistor to both the anodes.
I buy all my decoders and LEDs from www.litchfieldstation.com