I would like to start putting led headlights in many of my engines. I would be great to be able to just remove the plastic lens that is there now and be to insert a bulb or bulbs back in the same holes. I need to know to know what size I might be looking for, where to buy them, and what size resistor they take? I have done a few of my F7’s with a 5mm and a 1000 ohm resistor but the nose and cab lights on my other engines need a much smaller bulb.
Thanks in advance for the help.
What you NEED to do is what different engines require.
Grain of Rice bulbs seem to fit more engines, and can be driven with a simple bridge rectifier in series with the motor, plus C.V. kit’s are available for the more electronically challenged individual See Walthers Catalog…
LEDs are more complicated and require more than a resistor for constant brightness.
MY GOR bulbs are 1.5V and a bridge rectifier provides 1.4V in BOTH directions, for steam, or two diodes do it in One direction for diesels, Also the color is right…
I recommend 15ma for dual diesel lights, and 30 ma for brass steam. 15 ma doesn’t melt the plastic.
I’ve yet to burn out a bulb, but I’ve managed to fry a number of LED’s.
Don,
I have a number of desiels with the 1.5V 30MA grain of rice bulbs installed and havent had a problem. Not too mention, they spend a good chunk of their time running around in 90 degree plus heat.
But that being said… Kinda got me concerned. Have you had some fail on you? How long were they on?
Frisco - are you running DC or DCC? That’s going to make a big difference in how you wire LEDs.
I run DCC. I like the 3mm “Golden White” LEDs, although I’ve got a couple of engines with 5mm LEDs in them, and they work OK, too. I use a 1K resistor for these. I get the LEDs at my LHS, and the resistors from Radio Shack.
Frisco - If you are running DCC then I think LEDs are the way to go. No additional circuitry with the exception of a quarter watt resister. I use white 5mm LEDs with a 640 ohm resister on my F1/F2 locos. I like to do night ops and the bright 5mm white LEDs really lite up the track. On my Gps I usually only have room for the 3mm white LED. I just place the LED behind the len/s. If using a white LED then any resisiter between 640 and 1000 ohms will work just fine. You can replace the lens with the LED but it would look better if you glued the LED in place so it shines thru the lens or what I do sometimes is cut a piece of shrink tubing the size of the LED and slide it over the lens and slip the LED into the sleeve. LED only work one way so if it doesn’t work when you wire it up just reverse the leads and it should work. It does not hurt it to hook it up backwards it just won’t work. THe LEDs will outlast the other type bulbs by years and the LEDs put out more light. LED light patterns are like a cone they project light out in front of the loco and it looks realistic. If you want to go with a more proto look the Golden White LEDs Mr B mentioned are nice looking. Check this video out of a C-Liner with a 5mm White LED. Put on your sunglasses first. When i turn out the lights and have my C-Liner and two FA units running the layout the light show is really nice.
Give me a few minutes and I will get on my other computer and look up some LED venders. I buy LEDs by the 100 pack for ten cents a piece. Resistors are even cheaper.
By the way it was mentioned that constant brightness could be a problem.That must be a DC Problem because my LEDs are constant regardless of throtttle setting or location on the track. I can’t talk DC as I have always been DCC.
Sorry for the delay in getting back to everyone but work was calling. I run DC on my layout at the present time. I have already installed LED’s in my F7’s but want to start on all of my others such as the SD45’s, SD 40-2’s and a bunch of GP 38’s, 50’s and 60’s. I appreciate all the help and will pay a visit to Radio Shack soon. I already know that they, or at least the one here, does not carry 3mm LED’s.
I disagree highly!!! I can put in an LED in just a few minutes. Plus you said it takes more than a resistor to make them work- you are very wrong!! All I use is a resistor and electricity. They are the brightest I have seen and last longer than a small bulb any day. I have had the same LEDs in my locomotives for more than 2 years and they still have not died. A friend of mine bought those grain of rice bulbs, placed them in his locmotive and they burned out in less than a month. Same with Athearn RTR. They have those bulbs in them and my friend lost most of them in a month.
there quite worthless when you have to keep changing them out every month.
James
look at miniatronics, the LHS had a fair selection and modt LED’s were sold with a resistor.
HI there. I am also putting in LEDs of the white yellow variety as time etc permits. Spend a few extra cents and put a power diode in series with it, say a 4004. LED’s are not good at taking voltage in reverse, i.e when you back the train on plain DC anyway. They are rated up to 80,000 hours which is about the time my wife thinks I spend a week on the hobby! 
My Website www.xdford.digitalzones.com and follow the links although I have not got one for the LED’s yet!
Cheers from Down Under
Trevor