Adding LEDs to LokSound Decoder

[Mainline913]

I recently added a Loksound decoder to an HO scale SD40-2 Mid. I think the decoder has amazing sound compared to Digitrax, and QSI. The quality of the bulbs are horrible though. The SD40-2 has ditch lights and they are barely even noticeable with the loksound bulbs. I want to upgrade the bulbs with bright white LEDS. I am thinking of using a 3mm, or 5mm bulb to do this. I have never added LEDs to anything. I realize that I will need resistors but beyond that I am lost. I assume I pop out the current bulbs out of the dcc board and solder the LEDs to the spot where the old bulbs where. Is there a particular size of resistor that I should use? Does anyone have a photo or a diagram of a decoder that they added LEDs to? The kato has plastic light tubes to run the light to the lenses which I will keep but I may place the bulbs in the tubes and take them off the DCC board. Any tips or thoughts would be greatly appreciated.

[Mainline913]

It is more than just the light tubes. I have another SD40-2 mid with a digitrax decoder that uses bright LEDs. I also black out the front and rear number boards and trim down the light tubes to direct more light to the headlights. I have done this in both engines. There is just a huge difference between the two. I think you lose some light in the tubes but the one with LEDs looks great to me even using the tubes. I will throw a pic on this post to show you the difference in the two.

[Mainline913]

Here is a link to a photo to show the difference in the two SD40-2s. The BN has the loksound decoder with poor lighting. The gray CEFX has a digitrax decoder with LEDs. Both engines are using the KATO light tubes to run the light from the board to the lenses. http://s675.photobucket.com/albums/vv120/biz816/

[locoi1sa]

 When I instal LEDs I bypass the loco board and use a 1K 1/4 watt resistor straight to the decoder. On most loco boards there are some uneeded diodes and caps that rob and do some strange things to decoders.

 I only have one modern diesel with ditch lights and put bright white 3 mm LEDs in the pilot. I sanded a flat spot on the end of the LED and polished it with some real fine crocus cloth and put some shrink wrap on the outside to block light from escaping. Looks and works great.

   Pete

[Mainline913]

">. Need some pointers and tips to upgrade the BN loco with LEDs.

[tstage]

Mainline,

With LEDs and light pipes: I find that black heat shrink around the tip of the LED and the end of the light pipe keeps them connected together AND helps to better focus the LED light down the length of the light pipe - with very little light bleeding.  If the LED is in a prominent place, you could always paint the back of it black to mask any bleeding.

Tom

[Graffen]

 Extremely nice light you have there David! How do you go about doing that if I may ask? What components?

[rrinker]

 The hardware part is easy, white LEDs with 1K resistors on each one. The mechanics of the fiber optics, that's another thing entirely.

                             --Randy

[rrinker]

470 or 560? I refuse to be tricked   570 is not a standard value. 18-15ma, live dangerously (assuming 12V at the function output. I changed the 470's in my Stewart VO-1000 to 1K and the darn things are STILL too bright. Illuminate the track ahead, yes. Illuminate the whole layout room just by turning on the lights of one loco, no - if I need a flashlight there's always the DT400.

 I only use 1 or 2 brands of LEDs, and a 1K results in 9-10ma, which makes them plenty bright to light up the track ahead. Loss from the fiber optics will require slightly brighter, but for direct view, definitely too bright with the 470.

                                      --Randy