Im new to all this and have aquired a few Loco’s that have burnt out bulbs. Im good on the soldering, but not so good on figuring what size grain of wheat bulbs i should be looking for. What Voltage/Ma should I be looking for. I have mostly Bachmann with 1 Athearn. Any help ing the right direction would be greatly apreciated. THANKS
I would recommend replacing your old bulbs with Light Emitting Diodes, LEDs. 3mm or 5mm ones work best, depending on the size of the openings in the engines. Get a 1000 ohm (1K) resistor for each LED. LEDs are polarized so if you’re using DC you must get the polarity right. As long as you have a resistor in series with the LED, wiring them backwards won’t hurt - they just won’t light.
I personally like the “yellow white” or “warm white” LEDs to better model older locomotives. “Bright white” will work for modern engines.
If you are using DCC, you may (or may not) get by without the resistor, because some decoders have them built in.
LEDs have several advantages for headlights. They are cool, and won’t melt your shell no matter how they are installed. They are bright and give a very direction beam, just like real headlights, so they cast a nice light down the track. They will also likely last forever, so the next time you need to remove the shell, it won’t be to replace a headlight.
Hi Yodarian:
In case nobody has said it, WELCOME to the forums. [#welcome]
I’ll second the suggestion to use LEDs instead of incandescent bulbs for all the reasons mentioned by MisterBeasley. If you tell us which specific locomotives you are working on we will probably be able to make some more detailed recommendations as to what size LEDs to use and how to mount them. Also, are you using DC or DCC control?
Bottom line is that bulbs will eventually burn out. LEDs will literally last for thousands of hours. Don’t forget the resistors if your decoder doesn’t have them built in!
Dave
thanks for the welcome. I have 4 Bachmann GP40’s, 1 Athearn GP40, 1 Spectrumm by Bachmann SD45, 1 Bachmann FT A unit, 1 Bachmann Hogwarts Express, and 2 GE Dash 8-40CW. some came already with DCC, the others I installed Bachmann EZ command decoders into. I’m just running a basic Bachmann EZ command throttle. I have other Locos but they are dummies or i have decided to leave in DC configuration. If you are willing to help with some info…i would really love to learn how to wire a LED and possible make a flashing LED. any help would be awesome.
I’m not sure what you know about LEDs already so be patient with me if some of this is too basic.
First, ‘white’ LEDs come in several versions of white ranging from ‘ultra’ white to ‘warm’ white. For your purposes I would suggest using warm white or ‘sunny’ white. The ultra white LEDs have a decidedly blue tint to them which doesn’t look particularly like an incandescent bulb.
LEDs come in several sizes. The best size for your applications may vary a bit from locomotive to locomotive depending on the headlight configuration. Typical sizes are 5mm, 3mm, 1.8mm for the type of LEDs that come with built in solid leads, and ‘0603’ or ‘0402’ LEDs to which the wires have to be added directly (no leads unless you buy them with wires already soldered on). ‘0603’ refers to the size i.e. .060" x .030". They are often referred to as ‘SMD’ LEDs (Surface Mount Device).
For your FT A unit you may find that a 3mm LED will fit very nicely where the existing headlight lens is now. I’m not familiar with the insides of the other units but you likely have some choices in terms of where the LEDs are going to be mounted. You can put them where the existing light bulbs are now, but often that doesn’t give the best illumination. The advantage is that in most cases your number boards will still light up if the system is only using one bulb to light everything. If you have separate bulbs for the headlights and number boards then you should use separate LEDs obviously.
The other option in terms on locating the LEDs is to eliminate the light tubes and attach the LEDs directly to the back of the lenses. That often opens up a lot of space inside the shell if you are considering sound. I like to use 0603s for this because they take up so little space and they give out just as much light. If you have twin headlights and want to get the best lighting I suggest using two LEDs.
One trick I have learned is to apply pow
Thanks for the info, but sadly there are a few things I did not understand.
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How do you know the positive side of an LED?
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what side of the LED does the resistor get soldered to?
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does it matter what side of the risisttor is soldered to the LED?
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and lastly, what is meant by soldered in series?
sorry for sounding so dumb, but I’m just learning to work with electrical stuff.
Hi Yodarian
Those are all legitimate questions. No need to apologise.
You can tell the positive side of an LED in a couple of ways.
If you are working with 3mm or 5mm round LEDs you will see that one lead is slightly longer than the other. The longer lead is positive. If you are looking at the small SMD 0603s there will be a symbol on the back, usually in green, that is shaped either like a triangle or a ‘T’. The wide end of the triangle or the top of the T point towards the positive solder tab.
The other method is to simply test the LEDs. I have a power supply attached to my workbench that puts out 12 volts. It has red and black aligator clip leads, red being positive. If you are going to use 12 volts you MUST have a resistor in series with the LED (I’ll explain ‘series’ lower down) or you will blow the LED instantly. Just hook up the LED and resistor and turn on the power. If the leads are connected with the proper polarity, i.e. positive to positive, negative to negative, the LED will light. If it doesn’t light you won’t have done any harm. Just reverse the leads and the LED should light up.
There are two basic ways that components can be connected - ‘series’ and ‘parallel’.
‘Series’ means that the second component is connected to one lead of the first component so the power flows first through one component and then through the other. In the case of an LED and a resistor, one side of the resistor is attached to one of the LED leads and the other side of the resistor is attached to one side of the power supply. The other LED lead is attached directly to the other side of the power supply. Therefore, the electricity flows from the power supply through the resistor and then through the LED and then back to the power supply. It doesn’t matter which lead the resistor is attached to.
‘Parallel’ means that two components are wired so the power goes
thank you for breaking that down for me…i will be looking up your suggestions. as for if im running DC or DCC…as stated in my first reply, I have installed EZ bachmann DCC decoders in all the loco’s I wanted and am running with a basic Bachmann EZ command throttle. the one thing i didn’t see in your reply was does it matter which way the resistor is installed.
Hi Yodarian
Sorry, I forgot that you had mentioned the Bachmann DCC system. Brain fart.
It doesn’t matter which way the resistor goes.
Dave
I’m looking forward to practicing some of the things you have told me. i will be sure to let you know how things work out. I can’t thank you Dave enough for all the help. I’m so thankful i found this forum.
Sincerly,
Paul
Yodarian:
You are most welcome. I’m glad you were able to make it through my long winded answers[swg].
Dave
Your answers are not long winded. they were very helpful. I may not be young, but sometimes i need help. I not fond of reading thru books. so when im able to get info without a bunch of other stuff to filter thru always is a great help. thanks again.
Paul
Wow, this is the LED info. I’ve been looking for! So glad to have found it, guys. Thanks!
CNWman:
Don’t be afraid to ask more questions.
Glad we could help.
Dave
I use 12 volt 3mm warm white LED’s for most of my headlights and don’t need the resistor as it is built into the LED. I get mine from LED-Switch company or All Electronics, both good sources for LED’s. Just another option when doing LED installations for headlights. If your DCC decoder is set up for 3 volt lighting then you just need the regular LED, not the 12 volt one and no resistor. Hope this doesn’t confuse you but I like to keep my wiring as simple as possible.
-Bob