Re: Wiring the LEDs in a DC wired loco for DCC
You did not specify the type or scale of the engine so my comments are theoretical. Should the decoder be a basic hard wired type powering lamps then the following in theory, depending upon if you want to turn the forward and rear headlights on/off, and depending upon the decoder used, this should work for your situation. You will most likely need to add on the negative leg of each LED a resistor to adjust for brightness. 1/8 amp resistors will most likely get the job done.
Connect all eight of the LEDs positive lead to the blue wire of the decoder.
Connect the front white LEDs and the rear red LEDs to the white wire of the decoder.
Connect the front red LEDs and the rear white LEDs to the yellow wire of the decoder.
In essence when the engine is set to move forward, and the headlight function is turned on, the front white LEDs will light up and the rear red LEDs will light up. When the engine is set to move backwards, and the headlight function is turned on, the rear white LEDs will light up and the front red LEDS will light up.
I did something similar to a N scale doodlebug a couple of years ago.
You might want to test the above first to insure of the value of the resistors before you wire the headlights of your engine. It will be easier to swap out different value resistors in order to get the proper brightness of the LED.
Sent: Wednesday, May 1, 2019 1:17 PM
Subject: [w4dccqa] Wiring the LEDs in a DC wired loco for DCC
I have a DC loco that has 4 LEDs front and rear. There are two white LEDs and two red LEDs at each end.
When running forward in DC mode the two white LEDS light up and two red LEDs in the rear light up and vice versa.
I would like to install a decoder into the loco but I am not sure how to wire the LEDs so that I get the same functionality.
The LED terminals are not all visible. I fact there are only 4 leads coming from each bank of LEDs.
I am not sure how to up load a diagram to show the existing wiring layout.
Is anyone able to assist me?