 Joined: 10/02/2021(UTC) Posts: 3,892 Location: Michigan, Troy
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Has anyone else encountered this? I bought a reel tape strip of cool white leds. You can cut them every three. I used 15. The first two dim fine with one resistor. The third didn't even dim with two. I don't need to use any more at this time. The strip has a black retcangular electronic component for each led. 
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 Joined: 11/07/2018(UTC) Posts: 217 Location: Aruba (general), Oranjestad
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What value resistor did you use?
Did the same over the week-end
I used cut of 9 sets of 3 from the reel, enough for one coach, i use 2 x 10K (one on + and one on -, works like a charm...
Regards
Jean-Pierre
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 1 user liked this useful post by cintrans
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Joined: 10/02/2021(UTC) Posts: 3,892 Location: Michigan, Troy
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I used 2.2 ohm, 1/2 watt 6%. Been using them since last year. I also used first off the reell, two sets of 12 and they worked great. It must be something in the strip.
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 Joined: 23/07/2014(UTC) Posts: 8,475 Location: ENGLAND, Didcot
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Originally Posted by: marklinist5999  I used 2.2 ohm, 1/2 watt 6%. Been using them since last year. I also used first off the reell, two sets of 12 and they worked great. It must be something in the strip. 2.2 ohm, or 2.2kohm? I would expect the latter (3 red rings on the resistor).
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1 user liked this useful post by kiwiAlan
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Joined: 10/02/2021(UTC) Posts: 3,892 Location: Michigan, Troy
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Yes Alan, 2 red rings, 2 silver on a tan resistor. My multimeter read 2.5 ohms at the lowest setting of 200ohm. Two read 4.8 ohms.
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Joined: 23/07/2014(UTC) Posts: 8,475 Location: ENGLAND, Didcot
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Originally Posted by: marklinist5999 Yes Alan, 2 red rings, 2 silver on a tan resistor. My multimeter read 2.5 ohms at the lowest setting of 200ohm. Two read 4.8 ohms. That will not change the current very much at all. Is the strip rated at 12V or 5V? It will have a resistor in series already to limit the maximum current if so, and the resistor you are adding will be peanuts in comparison. Are you looking to change the brightness at all?
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1 user liked this useful post by kiwiAlan
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Joined: 10/02/2021(UTC) Posts: 3,892 Location: Michigan, Troy
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The strip is rated at 12 volts. Yes there are black diodes or resistors for each led. I checked them frst without a resistor, and they were way brighter. I would like it dimmer in the one car that is brighter. I don't get why the other 3 cars are much dimmer. I used the identical resistor in those. Is it possible that the built in resistor is every so many, and theat last car doesn't have one? It isn't visible on the strip along the rest of it on the reel.
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Joined: 11/07/2018(UTC) Posts: 217 Location: Aruba (general), Oranjestad
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 Hi Are we talking about the same type of reel / strip? I used these. They are also rated 12V, mine are "warm white" The black rectangular device is a 100 ohm SMD resistor. As i wrote, i cut of a strip of a total of 27 LED's, fed them with 2 x 10.000 ohm resistors and the brightness is just right for a coach. The three LED's and the one resistor are connected in series with each other, at least in the reel i have, if the resistor is not present it will be an open circuit an therefore the LED' will not light up... Are you sure about the resistors you are using? Red, red, silver, silver rings gives you 0.22 ohms at 10% tolerance Jean-Pierre
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1 user liked this useful post by cintrans
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Joined: 10/02/2021(UTC) Posts: 3,892 Location: Michigan, Troy
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Yes, the reel looks like yours. I posted a color error on the silver rings. They're gold rings. As I said, I've used these before, and even with only 3 or 6 leds on the strip, they were perfect.
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 Joined: 30/08/2002(UTC) Posts: 1,288
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Originally Posted by: marklinist5999 Yes, the reel looks like yours. I posted a color error on the silver rings. They're gold rings. As I said, I've used these before, and even with only 3 or 6 leds on the strip, they were perfect. I also endorse the input given by kiwiAlan and others in this thread; A 2.2 Ohm resistor wouldn’t affect perceived brightness on your LED strip; The resistors probably were in the magnitude of > 1000 Ohm (1 kOhm). Are you sure your previous resistors weren’t marked Red Red Red Gold (2.2 kOhm) instead of Red Red Gold Gold? |
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1 user liked this useful post by PeFu
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Joined: 10/02/2021(UTC) Posts: 3,892 Location: Michigan, Troy
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Yes PeFu, they are exactly identical resistors. I just tested a strip of 9, and they didn't even light without a resistor, so I cut off three, and still nothing. I wired up the row of three, and they're dead too. These are SMD 5050 leds 3.5 amps. IP grade IP65. Also water proof. I just peel back the silicone over the top enough to expose the solder points.
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Joined: 11/07/2018(UTC) Posts: 217 Location: Aruba (general), Oranjestad
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Can you post a picture of those LED's?
3.5A sounds very high to me for LED's....
Jean-Pierre
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1 user liked this useful post by cintrans
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Joined: 23/07/2014(UTC) Posts: 8,475 Location: ENGLAND, Didcot
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Originally Posted by: cintrans Can you post a picture of those LED's?
3.5A sounds very high to me for LED's....
Jean-Pierre It may be 3.5A for the full reel of LEDs when supplied with 12V. But a single section of 3 LEDs should be in the range of 10-20mA, on the basis that there are 3 LEDs plus a 100 ohm (or more) resistor. To the original poster, you do need to be careful where you cut the LED strip, to make sure you get the correct block of three LEDs, otherwise the connection to the LEDs gets screwed up.
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1 user liked this useful post by kiwiAlan
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Joined: 10/02/2021(UTC) Posts: 3,892 Location: Michigan, Troy
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Ah, that's what I was thinking Alan. Now I don't know where to cut the strip so they work again. Amazon quality. These were only $11.99 for the reel. The Evemodel pre wired 3 led strips are $9 for only a 10 count of 3 on each led stips.
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Joined: 23/07/2014(UTC) Posts: 8,475 Location: ENGLAND, Didcot
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Originally Posted by: marklinist5999 Ah, that's what I was thinking Alan. Now I don't know where to cut the strip so they work again. Amazon quality. These were only $11.99 for the reel. The Evemodel pre wired 3 led strips are $9 for only a 10 count of 3 on each led stips. Does your strip not have exposed pads every so often, like that pictured by jean-Pierre above? Note that at on the right hand side of the picture at the end of the strip there are two pads marked '+' and '-', then every three LEDs as you move to the left there are another set of pads. These should be the cut points. You then need to connect them to the correct polarity voltage. You can buy miniature rectifiers that have a full bridge rectifier in one package, with the '+' and '-' leads on one side and the 'AC' leads on the other side. One of these and a small capacitor (to stop the LEDs flickering) of about 10uF 35V should be sufficient.
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1 user liked this useful post by kiwiAlan
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Joined: 10/02/2021(UTC) Posts: 3,892 Location: Michigan, Troy
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yes Alan, it has copper pads every three.
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Joined: 10/02/2021(UTC) Posts: 3,892 Location: Michigan, Troy
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The consecutive 6 light up at least, but no dimming, even with 2 resistors.
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 Joined: 04/04/2013(UTC) Posts: 1,291 Location: Port Moody, BC
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Originally Posted by: marklinist5999 The consecutive 6 light up at least, but no dimming, even with 2 resistors. If you are not getting any dimming then the resistor value must be very low. Try a 10k ohm resistor in one of the DC power leads and see if you get dimming.
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1 user liked this useful post by PMPeter
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Joined: 10/02/2021(UTC) Posts: 3,892 Location: Michigan, Troy
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Joined: 04/04/2013(UTC) Posts: 1,291 Location: Port Moody, BC
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Originally Posted by: marklinist5999 Thank you Peter! Does this mean it worked?
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1 user liked this useful post by PMPeter
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Joined: 10/02/2021(UTC) Posts: 3,892 Location: Michigan, Troy
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I havn't ordered any yet Peter. First, I'm trying to wire two of the ones I have together SxS with one wire in and out to the strip. As only one worked before. I tried two in line series and nada.
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1 user liked this useful post by marklinist5999
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Joined: 10/02/2021(UTC) Posts: 3,892 Location: Michigan, Troy
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Still too btight, and now buzz. I have only one more car to light, and all these leds, plus 95 of theses too weak resistors.
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Joined: 04/04/2013(UTC) Posts: 1,291 Location: Port Moody, BC
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Originally Posted by: marklinist5999 Still too btight, and now buzz. I have only one more car to light, and all these leds, plus 95 of theses too weak resistors. Something is obviously wrong. Can you send a picture of what your connection looks like or a schematic of the set up?
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1 user liked this useful post by PMPeter
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Joined: 10/02/2021(UTC) Posts: 3,892 Location: Michigan, Troy
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Peter, I truly appreciate your help! They also blink on a/c, because they need recitification. I put them in my Wurttemberger cars for 3 rail. They weren't blinking on my test track with my 6021 because I hadn't entered an address. I'm bad at uploading pics. here. I have to shoot with my phone or tablet, send to my e-mail, and attach here. I forgot how to.
I soldered 2 resistors together at both ends with matching colors side by side, and a wire on each end of them. One end to the pickup shoe, one to the leds. I also put one resistor on the other end of the leds to the ground axle spring.
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Joined: 04/04/2013(UTC) Posts: 1,291 Location: Port Moody, BC
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When you solder 2 resistors together side by side you are connecting them in parallel and then by Ohm's law you are cutting the resistance in half. For example if you connect 2 - 100 ohm resistors in series your total resistance is 200 ohms. If you connect 2 - 100 ohm resistors in parallel the total resistance becomes 50 ohms.
You should only have resistors in one of your power leads, not both. I would really like to see a picture. Can you use the PM or e-mail feature on this site?
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Joined: 11/07/2018(UTC) Posts: 217 Location: Aruba (general), Oranjestad
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Look at this tutorial video from one of the forum members: One of the better ones on the web explaining how to use those LED's from a reel. Regards Jean-Pierre
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2 users liked this useful post by cintrans
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Joined: 10/02/2021(UTC) Posts: 3,892 Location: Michigan, Troy
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Very good video! I never heard of routing wires through the nem pocket before. When ordering electronic parts from Amazon the photos and or descriptions don't always match what you receive. The bridge rectifiers for example. I ordered two and they're both on one board, but have capacitors. Also red pilot LEDs.
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Joined: 10/02/2021(UTC) Posts: 3,892 Location: Michigan, Troy
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One point I noticed he did was cement the ground spring to the bogie. I usually just remove one wheelset, and slide one end under the other axle, then clip the wheels back on over the springs. They usuallly make good axle contact. If not, just bend them up a bit. Some cars have one axle which comes off easily, and one that doesn't go back on without using a flat wedge to spreadthe holding clip apart a tad to get the axle back on.
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