LED Light Specs Lionel 6-85050 Legacy SD-70AXe

Carl,

Lionel Parts shows two kinds of LED assemblies for your SD-70 AXe ...

... which look like this:

  1.) Ditch Lights --

  2.) Ground Lights --

Both of them are chips, and not the packaged LEDs we normally use.  Are you thinking of removing and replacing the chips?  Or perhaps replacing these entire assemblies with standard cylindrical packaged LEDs, either 3mm or 5mm in diameter?

Mike

   Good afternoon Mike,

   Yes, I plan on replacing the Legacy chip LED's with warm white 1.8mm Bulb LED's.

   I'm unsure as to the voltage being supplied to the Lionel Legacy LED's,  3VDC or ?

   Best Regards,

   Carl

The white ones will be 3V and 20milliamps max, that's what a vast majority of all the LED's you see in model trains will be.  Red ones are closer to 2V and also a max of 20milliamps.

Carl,

What John said.  White LEDs of this size, whether chip or packaged, usually have an operating current of between 15 and 20 mA.  If they are supplied with a current level in this range you will see a voltage drop of at most 3.5v across them.

I chose my words very carefully.  It's tempting to think of LEDs as though they're common incandescent lamps, but they're not.  This is because LEDs are current-driven and not voltage-driven.  What does this mean to you?  Absolutely nothing given what you're planning to do, as long as you're replacing white with white.  On the other hand if you're replacing white with red, yellow, green, or blue, it makes a big difference.

If you change colors you will need to change the value of the series resistor that is presently connected to the respective LED.  If no change in color, no change in resistor.

Mike

   Thanks' Guy's,

   That is the information I need to get started on the lights. I must say, Lionel's Legacy System certainly does have a toolbox full of wonderful features.

   Scott from ERR warned me about the different voltage LED/Incandescent light issues when using his equipment, so I am treading lightly with the Legacy Equipment.

   Warm Regards,

   Carl