So far I have been replacing the lamps with LEDs for all Soundtraxx
decoders. I have one 0-8-0 with the lamps hard to reach, and the only
reason to take the loco apart is to get to the forward lamp. Remind me
again, why am I replacing these 12 V bulbs with LEDs? Will the bulbs
melt the shells otherwise?
Because when you are done changing it make sure you leave your heirs pictures of how you did it. That is the next time it will need changing.
Generally people consider the longevity of them over bulbs. However, that is usually because they run a 12V lamp at 12V or higher, so it is no wonder they burn out quickly. The melting effect is there too. A 12V bulb puts out a ton of heat especially at 13V. Our DCC system melted many shells with light bulbs when we were running it at 17.5V.
I don’t generally use LEDs. I got a couple of the 3mm golden-glow LEDs that worked ok, but I love the tiny 1.5V incandesant light bulbs. I run them at 1.2V and they last forever too. The tiny size makes them fit in many places that require specialized LEDs. Ohms law applies to light blubs which is nice benefit over LEDs. The incandesant light bulbs allow one to use all the lighting effects of the decoders too. I’ve never seen an LED make a good strobe, mars, or gyra-light.
But doing it my way, one still ends up doing surgery on the locomotives, so if that is your only big issue you might as well stick with the LEDs.
LEDs, or Light Emitting Diodes, use far less power than incandescent bulbs. If you are using a lot of them, that will make a difference, but realistically it’s not much of a factor in a loco headlight. Most of that extra power the incandescents use ends up as heat. In a plastic-shell engine that’s not designed for it, that could actually melt the shell, but since your incandescent bulb came with the engine, that should not be a problem either.
A typical incandescent bulb gives off a yellow glow in all directions. LEDs give off either bright white light, or a number of colors. I personally like the “golden yellow” or “golden white” LEDs, because I’m still trying to simulate an incandescent, even when using a LED. LEDs do not give off light evenly. Instead, they “beam” it out, much light a real headlight, in one direction. This beam is generally much brighter than a similar incandescent, too, so LEDs do have the edge if you want a really bright, strong headlight. I personally like that effect on my layout, but some don’t.
Properly wired LEDs will probably out-live the locomotive. An incandescent bulb can last for many years, too, if you run it at low voltage. Eventually, the incandescent will burn out an need to be replaced, but if it’s working now, you might just as well leave it in there.
So you don’t melt and warp the cab roof of your newest B-23 like someone I know.[:-^] I personally like the plain old white LED’s.
Are you using the LC series decoders or the Tsunamis? LEDs are perfect for the Tsunamis (make sure to change the cv that selects LED or Incandecent Bulb…), but LEDs for the LC is a little wierd…they will flash when you turn them off and make sound…
David
Go to this link for a solution to the flashing LED when using the SoundTraxx LC decoders. I did and it works fine now.
http://www.tonystrains.com/technews/soundtraxx-lcleds.htm
You might consider joining this Yahoo SoundTraxx DCC group. The trains.com forums are ok but more knowledge will be a great advantage to learning about DCC. Yahoo has other DCC groups also. All of the Yahoo groups have files and photos section that you can download material from. Belonging to only one or two groups can really cramp your style. You can also do a Google search for needed model railroad information. There is an immense amount of model railroad info available on the 'Net. Careful searching and reading will help a lot. You can then be more of a help in this forum.
http://groups.yahoo.com/group/soundtraxx/
rich
I use incandescent bulbs where convenient - they are inexpensive and the LHS owner recommended them to me when I converted to DCC, but LED’s have another advantage not yet mentioned. Incandescent bulbs have a high inrush current when first turned on. They will draw 10-20 times as much current for a few milliseconds until the filament heats up. This can stress the driver components on the decoders, so they should be ‘derated’. In other words, you should use an incandescent which draws only a fraction of the current the decoder output is rated for. LED’s don’t have this inrush problem. In practice, a low-power incandescent bulb should be just fine. Like I said, that’s mostly what I’ve used, and I haven’t had any problems so far.
Jim
Thanks for the info.
David
LED’s are brighter, longer lasting, less energy hungry, easier to use, and smaller than incandescent bulbs. Ask yourself that question again when you’ve finished the conversion and the answer will be self evident. For the uber upgrades go with fiber optics. I assume you are in HO scale, so I don’t know much about fiber optic upgrades for you, but in G scale, in my mind there is no other way than LED and FO (mixed methods are OK too).
Hardly, I see more posts out here of people asking how to install them, or asking what they have done wrong. People try to treat them just like light bulbs (using Ohm’s & Kirchhoff’s laws) in series and parallel circuits which gets them in trouble. They are polarity sensitive which causes more consideration for installation. How is any of that easier? I don’t recall seeing any posts lately on “how do I install a light bulb”.
You must be thinking about the old fashioned “grain-of-wheat” bulbs from the 1970s. The ones I am talking about (that came out in the early 1980s) are the size of the head of a pin. The only LED I’ve found even close in size are the ones that have the “lens” made into a funnel shape. Even at that only the front part is small. One must deal with the huge “back” part. Actually the LED junction is extremely small. They just need all that mass to keep the wires coming externally for connections from breaking off. Now there is an LED someone should develop. Contact connections so the LED could just touch (like the two halfs of a Bachmann split frame) the power from each side. Eliminate the wires altogether. LEDs small enough for N-scale marker lamps!
TZ…I like to use Surface Mount LEDs for my Ditchlights. And for a double pyle headlight, ill solder 2 SMT LEDS end to end. These LEDS are the size of a grain of sand, and they put off enough light to make you want to look away.
I should do a HOW-TO make ditchlights, but Im afraid on these forums people are on the shakeandbake side of things.
David
Texas,
Yes I am thinking of the old grain of wheat bulbs. My mistake and thank you for pointing that out. Sometimes my technology thinking is still in the ‘70s.
As far as being easier to use, they are for me. Maybe it’s my long experience with them that I sometimes forget others don’t know what I know, again thanks for clearing that up.
My point is regardless, once you convert to LED or fiber optic you realize the results are well worth the effort. I will never again use standard incandescent in any of my locos or other rolling stock, I’m sold on LEDs and fiber optics.
Yes. I’ve done 6 installs now all with LEDS. One has to put in the extra capacitor and resistor to overcome the flashing and glow with the Soundtraxx LCs and just a resistor with the Tsunami. Then add 128 to the CV for lighting on the Tsunami to “turn down” the LED a bit.
I just have a steam loco that is DCC ready and only would need the shell popped off for the LED. Since it is rather pristine, and my thumbs usually bend a few details around as I take shells off, I was looking to leave the incandescent bulb in place…but I think I will continue changing them.
RE Soundtraxx yahoo group…yes it is specific to Soundtraxx alright, but doesn’t have nearly the posting traffic of this nice forum. You forum guys are really helpful and fast.
As pointed out in a prior reply, the golden yellow and white LEDs can put out a very strong beam of light. This makes them an excellent choice for headlights. Fiber optics don’t put out much of a beam of light, but illuminate nicely. This makes FO and excellent choice for things like class lights, markers, or step lights.
Check out the soundtraxx yahoo group. The advantage to that group over this forum is the participants a more focused knowledge base than here. You’ll get an answer from people with a greater likelihood of having encountered the problem.
jktrains
LEDs are much easier to calculae resistence for than bulbs. LEDs ahve A current limit. That’s it. Bulbs have two internal resistances, cold and hot. Cold resistence is rather low, thus the use of a low value resistor with DCC decoders even when using 12V bulbs - to limit the turn-on surge which is some bulbs can exceed the decoder’s function output. And then when you try to use 1.5 volt bulbs - is it a 15ma bulb, a 30ma bulb, or what? Each takes a different resistor. And not just resistence value, but wattage rating. Some bulbs end up needed a resistor with such a high wattage, the RESISTOR will melt the shell, not the bullb. Such bulbs should, naturally, not be used.
Compared to an LED, which has a fixed and specified voltage drop and current limit. For DCC use, I haven’t seen a white LED yet where a 1K resistor wouldn’t work. Well, if you dig through a Digikey or Mouser catalog you can find some oddball specialty LEDs that don’t have the same current or voltage requirements, but if you order from any hobby supplier or get trhe Miniatronics ones - 1K is the ONLY resistor you will ever need. Yes, it matters which way you wire the LED - but hooking it up backwards won’t break it, it just won’t turn on.
&n
Easy to do, and case-in-point is the very next post. I’ve not never heard of these that davidmbedard mentioned → “Surface Mount LEDs … These LEDS are the size of a grain of sand, and they put off enough light to make you want to look away.” I mean I’ve heard of surface mount LEDs but none that small. I’ll have to check out a few of those, but limit the current a bit more to them to dim them down a bit.
Size: 1.6 x 1.8 x 0.6mm 0603 SMD LED 0603
That is tiny!..and you cant beat the price.
David
Here’s a closer pictureI’m not sure if there the same size tough.
The surface-mount LEDs are the ones used in electronics where a normal sized LED wouldn’t fit. I think a lot of cell phones use them to light the keypads. Same deal for anything with one of those plastic press-button surfaces (like a washing machine or microwave) that light up to show your selection.
They’re wicked small, a lot of times the actual diode part is smaller than the contact pads…