Hey folks. I need your help. This is the first time I am attempting to wire ditchlights to a decoder and I'm lost already. I have Richmond 603 Led's pre-wired to magnet wire. They came wired in only red, so I have no idea what is positive or negative. I also have a Digitrax DN163K1C decoder. The booklet has a picture of the function pads on the decoder and what they pertain to f1=green, f2=violet, f3=brown, f4=white/yellow). I would like to wire the ditchlights to flash when the funtion is programmed, so I am assuming the each light has to be wired to a seperate function? Finally, where do I solder the negative wires? There is another pad for +common (Blue). If thise gets to be too much I can always just have the ditchlights setup to simply come on with directional lighting. The LED's have a max of 20 milliamps. The decoder's function output is 500 milliamps.... so do I need to wire resistors in series? I may have bitten off more than I can chew. This is for N scale btw...
This is what I have been told by a local shop. (I will be adding leds and I am installing the digitrax SDH164D) The violet and green leads are to be soldered to the short lead of the LED with a resisitor attached. The long lead goes to the blue. Currently I am trying to figure the rest out. Since this is my first install I am a little hesitant myself to jsut jump in. I am glad you asked this question for I was about to do the same. Hopefully others will respond as well with more detailed info. Kevin
You can find out which lead is the anode (positive lead) and which is the cathode (negative lead) using an ohmmeter. Hook the LED to an ohmmeter and see if the LED lights. If the LED doesn't light switch the leads and see if it lights. When you get the LED to light the anode is the wire connected to the red meter lead. The two anode wires will go to the + common pad on the decoder. The cathode wires go to whichever functions you intend to program for the ditch lights. You will need a resistor for each LED. Try about a 1000 ohm resistor, this will limit the current to around 10 milliamps. It doesn't matter which wire from the LED you connect the resistor to. Kevin, 603 LEDs are surface mount devices, they don't have legs attached.
Ok, I ordered an led tester. Embarassingly enough, before I posted this thread I tried to test them with a AAA battery (1.5V) and now I am paranoid that I fried the LED... although I got no light at all when I did this, so if I did fry it, it happened faster than the LED could produce light... I'm sure its fine though. I will wait for the tester to arrive before I head to radio shack and pick up some resistors. Trouble is, the LED's are already installed in the ditchlight housings so if I need to change them out it will be a PITA... especially since they are CA'ed in...
If the LED didn't light at all make sure that the insulation is removed from the ends of the wires. With "magnet" wire the easiest way to strip the insulation is with a soldering iron. Get the iron hot, get a little bead of solder on the tip an then briefly put the end of the wire in the solder pool. As far as the speed at which components can burn out, it's faster then you can see. Always put a resistor in series with an LED when testing, however you may not have damaged the LED. Depending on the specific LED some take more then 1.5 volts to turn on.
