Athearn LED Lighting Upgrade

[NSDash09]

I have an athearn RTR C40-9W (Norfolk Southern) that i have modified to have the correct cab headlight. since I have the entire locomotive apart I figured that I might as well replace the bulbs now. Does anyone have any suggestions for what leds or bulbs i should use? Also, if i use leds will i need lenses on the outside since the old bulb is no longer there to act as a lens.

[warhammerdriver]

When I installed a decoder in an ancient small industrial switcher, I replaced the incandescent bulb with a 3mm white LED and used a 1K ohm, 1/4 watt resistor.  The domed led acts as the lens in my application.

I do wish I'd gone to a higher resistance with my resistor, though.  I think the LED's too bright.

Hope this stuff helps.

[rrinker]

 Where the LED is directly visible like that you may indeed need more than a 1K resistor. You'd have to experiment a bit because there is a rather abrupt cutoff betwween LED on and LED not visible at all. I've used almsot all 1K resistors, but most of my locos are P2K where the lights shine through a large chunk of clear plastic that acts as a light pipe. By the time it gets to the headlight lens, it looks about right. I have a couple of Stewarts which have a much better wuality piece of palstic between the LED and the lens - those I had to add more resistence to keep the light from being overly bright. They already had LEDs, just yellow ones, so I changed to a golden white (era approriate - for modern locos the sunny white type is a better choice) and added a 1K resistor in series with the existing 470 ohm one. It probably still could stand more resistence, next one I will try some other values to see if I can get it down a bit more.

 Jus goes to show how efficient LEDs are. Most white ones are rated to handle 20ma max. Using 1K resistors on a 12V supply, you get about 9ma, less than half the rated max. Yet as seen, sometimes still too bright.  Now if they just get the costs down for the big ones for home lighting, we'll be all set. There'dbe a HUGE savings over the typical 50 and 75 watt incandescent bulbs. And the same bulbs could be in the house for 40 or 50 years.

                     --Randy

 

[NSDash09]

Ulrich has a picture of a bunch of locomotives with 3mm leds installed but the athearn stock housings are 1.5mm and the Details Associate Pyle housing i got to add to the cab for the correct light is 2mm. Does anyone have any pictures for an install with the 3mm or suggestions as to size? I have some 2mm tower leds from miniatronics left over from my athearn P40DC (Heritage Phase III!) but i don't think i will room in the cab with the interior. Will the 3mm leds blast light throughout the entire locomotive?

[cedarwoodron]

A simple light pipe I have made is from clear sprue material leftover from structure projects. I rarely use the "supplied" window glazing plastic ( sheet clear plastic is much clearer) so I end up collecting these leftover clear parts and sprues. I use 1000 grit or higher to polish the ends, or a lower grit to put a diffused light-spreading face on the end of the light pipe. I seat the LED behind the light pipe and that seems to reduce the intensity of the LED's emitted light, rather than experimenting with a variety of resistors to reduce current levels. As is, a 1K resistor in a simple LED circuit will offer a very, very long lifetime of operation for the light, at model railroad electrical input levels. The light pipe does not have to be long, just sized properly to fit the headlight opening. A rounded appearance can be achieved on the end of the light pipe with proper sanding. Cedarwoodron

[rrinker]

 Of if you are picky or otherwise not inclined ot mess around with clear plastic, MV Products has lenses of just about every shape and size. You cna install one of those and put the LED behind it.

                 --Randy

[NSDash09]

So the led is just glued behind the opening? Does that mean you light the whole shell or can you focus it?

[rrinker]

 The light for a regular non-diffused LED general comes out the domed end, not much comes out the sides. Jut paint the sides away from the lens with flat black paint, or put shrink tubing over the LED to block the light.

          --Randy

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[fisker76]

Hi NS-

I use 0402 SMD LED's for locomotive lighting, both for headlights and ditch lights. You didn't say if this was part of a DCC project. For this conversation I'll assume it is DCC. 

For my LED installs, I glue the LED directly to Details West LN-341 light lens. The LN-341 fits perfect in the HL/RL of the Athearn RTR and Genesis models. I usually have to tint the LEDs with a clear orange paint made by Tamiya in order to get the proper color.

Check out this series  http://www.youtube.com/watch?v=YPLokrTiQJs I did on a  Sound install, it also covers the lighting.

[cedarwoodron]

Another tip- use shrink polyolefin tubing to hide any side light emissions, or just use flat black paint. Where there might be light spillage, I use black-painted blocking around the LED to minimize it. Cedarwoodron

[NSDash09]

A picture is worth a thousand words, So in 2000 words plus change here is what I have:

The nose holes will be filled in. The DA housing is 2mm in diameter.

If i understand correctly, the tower led i am using as a stand in will be replaced with a 3mm led that will hopefully not light the cab interior hiding in the corner of the first pic since I have a second led planned for that.

If anyone has an pics from an install they did that would help a lot.