Help
My decoder calls for 1.5V LEDs and I don't see how one can tell if they are 1.5V. Does anyone know for sure? They indicate they are for loco lighting.
Thanks.
Lee
3mmWalthers Part # 475-1231005, p. 773 Walthers 2011 HO Scale ReferenceA scale, $9.99, currently in stock at WalthersThis product is on-sale today for $8.98These LEDs feature a clear lens and combine the super-bright intensity of a white LED with the warm yellow glow of an incandescent lamp to make engine headlights more realistic. Choose from two different sizes to fit your favorite motive power.
Which decoder do you have?
Springfield PA
Yes they are. I use them all the time. To test them just hook a little battery up to them. They do a good job of imitating an incandescent light. In my opinion they look a little better after a touch with a yellow highlighter pen. Either way they are better then the so called white LEDs that emit a blue tinge. There are 2 different values of resistors in the same package. One is 320 ohms the other is 680 ohms.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
Hi Pete
The decoder is a Tsunami TSU AT1000 and the digram has a 1.5V outlet to the LEDs. Since I have 1.5V output from the decoder I should not need the resister?? Right? Oh, I was trying to get the information about the LEDs before I order them.
Thanks Guys
The TSU-AT1000 is a drop in replacement board made for Athearn loco's it does have a 1.5 volt output. Athearn loco's come with either 1.5 volt bulbs or LED's, usually bulbs.
I assume you're installing it in an Athearn?
What loco are you putting the decoder in?
The loco started life as an unpainted SD40 dummy shell. I picked up some trucks and a motor, there are no lights. Thats why I'm looking at The LEDs.
If you google 1.5 volt LED you'll find plenty of links for them.
Most white LEDs are 3.1-3.2 volts. Even common red/green/yellow LEDs are 2.1 volts. What I don't see in any of the various Tsunami manuals is if there is an alternate option to get full power. Other decoders that offer voltage or current limted outputs to work with LEDs withotu using external resistors usually have a different common connection for the blue wire that allows full power, such as if you wanted ot use 14v bulbs.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Hi Randy
I put one of the AT1000's in my Athearn SD60i. They are made to replace an athearn board and are set to the 1.5 volt bulbs that athearn uses. I didn't see anything to select a higher voltage.
locoi1sa There are 2 different values of resistors in the same package. One is 320 ohms the other is 680 ohms. Pete
There are 2 different values of resistors in the same package. One is 320 ohms the other is 680 ohms.
320 and 680 ohms?
The color bands on the Walthers ad http://www.walthers.com/exec/productinfo/475-1231005 shows the same as my 5 year old package below as 270 and 470 ohms.
Five years ago I installed these in three of the first Atlas DCC GP-40's ( Dual-Mode Lenz ) which had bulbs. I installed a 470 ohm resistor to front and rear light terminals and today they are still working and do have that incandescent yellowish look although at the time fellow modelers said I should have used 680 Ohms instead of 470. Yeah they are kind of bright but I like them.
Wadda ya mean I'm old ? Just because I remember gasoline at 9 cents a gallon and those big coal burning steamers.
You wouldn't need to use the resistors with the AT1000. Should be fine without since the voltage is 1.5
If the TSU1000AT is really limiting the voltage to 1.5, I wouldn;t expect them to light up at all. If they are instead actually limiting the current to the 15ma required by the small 1.5v light bulbs, then the LEDs will work fine with no resistor.
FOr normal, full voltage function outputs, a 1K resistor is most appropriate - in fact you might even want to go bigger ebcause the white LEDs are VERY bright. My Stewrat AS16 is a good example, I think it has 470 ohm resistors. The factory LEDs are yellow - not incadescent yellow, but yellow. I repalced them with the YeloGlo type, AND added an additional 1K resistor in series, adn they are really still too bright.
My three Tsunami equipped steam engines must have 1.5 volts applied to their LED's as both on bright and dim ( F11 ) are too dim for me. Have not had the tender shells off to check if resistor or not,but then again I don't need the light to see down the track so I'll let well enough alone.
Correct me if I'm wrong, but is the Tsunami AT 1000 the Atlas style board? While it will work just fine in any Athearn loco, the board's light output is 12 volts. The Tsunami GN1000 is for the Athearn Genesis series of locos and the light outputs are 1.5 volts with a 14 volt common that you must run the positive common to it.
Will
Actually you're right. I was thinking of Athearn for the AT. It's the GN1000 that is for Athearn
According to the soundtraxx write-up the voltage output is still 1.5 volts though.
http://www.soundtraxx.com/dsd/tsunami/1000at.php
Lee, you're going to have to verify the output for the light. Even though it says 1.5 volts on the write-up it might be higher. My Atlas loco's have a 1k resistor built in to the light board so the factory decoder is putting out 12 volts. I would expect the replacement board to be the same but it should be verified.
Hamltnblue
Yes the decoder does have a verified 1.5V output and What I really need is the 1.5V LEDs with out the resisters. I have a bunch of the resisters for future use. I guess I'm going to have buy the LEDs with the resisters anyway.
Thanks for all the responses.
I have seen this question before.
You probably know by now there is no such thing as a 1.5 volt LED. There are 1.5 volt bulbs and 20 ma LED's and 12 volt bulbs. I see this in different forums as some never do any research about LED's and bulbs and make assumptions which sometimes get them in trouble and burn out LED's or the LED does not light.
The instructions for the Tsunami show 1.5 volt BULBS, not LED's. The instructions very clearly tell you lighting for bulbs which are 12 to 14 volts or LED''s with a resistor to limit current. The instructions very clearly show you the common terminals for bulbs and LED's. The common for both are the same terminal. Get your ohm meter and and do a continuity check before you install the decoder.
Go to the SoundTraxx There are on line calculators for current, voltage. resistance, power, LED resistance, just about any kind of calculation your desire.
Ric h
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
The instructions for one or two Tsunami clearly tell you that there are LED outputs with the resistors on the decoder.
I have measured my Tsunami. The 1.5 volt are clearly 1.5 volt and regulated or they would not say 1.5 volt. The lighting for higher voltage bulbs is not regulated and no exact spec indicated and can depend on the actual operating voltage of the DCC controller which is why some in the past burned out 1.5 volt bus running off the only lighting connection which is 12 to 14 volts but if a DCC system runs at say 18 to twenty volts and some do, the resistor for the 1,5 volt bulb was not the correct value. No doubt why some decoder companies are going to 1.5 volt outputs and LED outputs.
Now someone will not read all of this and wonder why a resistor on the 1.5 volt bulb connection.
The documentation for DCC is not written by those who do model railroad DCC installs. The software is written by Geeks. Not model railroader DCC users.
Oh, Bean Counters control those groups and try to keep the cost lower.
Rich
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Thank you Rich, I am properly chastised. The diagram wording caused me to misinterpret the voltage the LEDs require.
The RIGHT way to do the outputs is to use current limited outputs, not voltage. That way they can work with 1.5V bulbs or LEDs which need more like 3.2 volts but can't handle more than 20ma.
As for the resistors that come with the Miniatronics LEDs - I have a box full of them. Neother one is the correct value for use with HO scale DCC so they just go into my parts box. Someday maybe I'll need resistors of that value.
ANd I am right now kickign myself for not ordering a bunch of 1K resistors from Mouser when I ordered my SMD ones for detection wheelsets, I could have added a box of them and not increased the shipping cost.
rrinker ANd I am right now kickign myself for not ordering a bunch of 1K resistors from Mouser when I ordered my SMD ones for detection wheelsets, I could have added a box of them and not increased the shipping cost. --Randy
Those SMD's are a lot of fun. I've got 80 axles done ( 80 cars ) so far. I'm using 1/10 watt 4.7 ohm SMD's using a standard tip CW Conductive pen. They really trip my signals. Love the little guys. Also ordered from Mouser.
rrinker The RIGHT way to do the outputs is to use current limited outputs, not voltage. That way they can work with 1.5V bulbs or LEDs which need more like 3.2 volts but can't handle more than 20ma. As for the resistors that come with the Miniatronics LEDs - I have a box full of them. Neother one is the correct value for use with HO scale DCC so they just go into my parts box. Someday maybe I'll need resistors of that value. ANd I am right now kickign myself for not ordering a bunch of 1K resistors from Mouser when I ordered my SMD ones for detection wheelsets, I could have added a box of them and not increased the shipping cost. --Randy
Very well put Randy ( you and I should make some mini-clinics on the electronics involved in DCC).
To ALL: The QSI Revolution is an example of a decoder that can use LED's or 1.5 V lamps with the same output. As Randy said, current regulation is the way, instead of voltage regulation. For example the ever popular golden-white LED's used for headlights have a operating current is very close to that of Miniatronics 1.5V, 15 ma lamps or the Athearn 1.5V, 12-15 ma "garden variety" lamps (no two are ever the same rating; put them in series, you'll see what I mean). In fact, the lamp board on current Genesis units have current regulation as opposed to voltage regulation. This method is also best for lamps as it prevents the turn on current rush that can shorten the lamps life.
For those curious, the LED's voltage drop is a product of the current it draws and the conductivity (or resistance if you want to look at it that way). In other words, if you have a current regulated output the voltage drop across the LED will match the rated value. You don't calculate it in this situation.
Carl in Florida - - - - - - - - - - We need an HO Amtrak SDP40F and GE U36B oh wait- We GOT THEM!
Some of the Digitrax DH165 series decoders also are current limited, default is 15ma which is great for LEDs but many low voltage bulbs are 30ma so they instruct you to cut a trace on the board to get 30ma.
The Tsunami has both 1.5 and 12 volt outputs. The 1.5 volt outputs are used for 1.5 volt BULBS. When using LEDs, you use the 12 volt outputs with the appropriate resistor (usually 1000 ohms). You should never run an LED without a resistor - even if the supply voltage is rated the same as the LED. Small, continuous voltage spikes can shorten the life of an LED.
The 12 volt outputs for front and rear headlights are the two middle contacts on both ends. The 1.5 volt pads are located on the central area of the board and are marked accordingly.
Mark.
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