I think I used a 22 gauge steel wire connected to an LED with a 1K 1/4ohm resistor. I soldered the LED to the blue (common+) wire to the anode side of the LED and the white wire to the cathode side of the LED coming from a Digitrax SDH164D decoder installed in a Proto 1000 RDC-1. The light of the sunny white LED does not go off completely when I turn it off with the F0 function button of my Digitrax DT402D throttle. The LED goes off only when I pinch the connected soldered joint wire on the cathode side. Is this happening because I am using 22 gauge steel wire? If not does anybody know why the LED is not going off? This is a picture of my decoder below.
OK so it is now soldered. (continuing with the same thread would keep all the information together and allow any new person joining the conversation to know all the details)
So what do we know? Current is flowing when it apparently should not be. When you touch the wire you are seemingly acting as a current sink and the lamp goes out.
Could be that you have enabled rule 17 head light dimming? or some other CV combination that does not turn the lamp off?
Could be that current is getting there from some other source than the decoder function output, perhaps the solder connections are touching metal somewhere?
Could be a bad function out put?
Try this....
Reset the decoder to see if this still happens.
Make sure there is no other possible conduction path for current.
Swap the front LED from the white to the yellow lead and see if the problem is still there when using the rear light function.
Have you tried to configure the lighting CV at all? This would be a great time to get your PR3 and Decoder Pro working so you can read back all the lighting CV's from the decoder to see how it is actually setup.
Simon Modelling CB&Q and Wabash See my slowly evolving layout on my picturetrail site http://www.picturetrail.com/simontrains and our videos at http://www.youtube.com/user/MrCrispybake?feature=mhum
Some older decoders were designed to use bulbs only. I have a couple of older Soundtraxx decoders that act the same way yours are, and everything is OK. They were designed for bulbs and I an using LED's with them. The later model decoders don't have this problem. Also, there may be a CV decoder setting that you need to change from bulbs to LED's. You will have to refer to the decoder manual to check.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
I just don;t get what pinching the wire has to do with anything, it's not like you can squeeze off the electrons like water in a garden hose. Digitrax decoders don;t do effects with LEDs very well, but I've not had one that couldn;t actually tuen off an LED. The issue is more liek when makign a flashign ditch light or beacon, the LED often barely gets any dimmer than the full on, which ruins the effect. But off - that's pretty much off.
Is the LED still connected to any of the factory board, or is it completely hardwired to the decoder? There might be a sneak path somewhere. You can also try adding more resistance -$1***$2a second 1K resistor in series, see if it goes off and yet is still bright enough when turned on.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
alloboard ...The light of the sunny white LED does not go off completely when I turn it off with the F0 function button of my Digitrax DT402D throttle...
...The light of the sunny white LED does not go off completely when I turn it off with the F0 function button of my Digitrax DT402D throttle...
When the LED does not go completely off, is what you get a faint flicker? If so, it sounds like Transponding is enabled on the decoder. Check the value of CV61 and if it is 2 or 3 then Transponding is enabled and you will get that flicker on the forward headlight output.
alloboard ...The LED goes off only when I pinch the connected soldered joint wire on the cathode side...
...The LED goes off only when I pinch the connected soldered joint wire on the cathode side...
That sounds like you may have a cold solder joint there.
CSX Robert That sounds like you may have a cold solder joint there.
I have to agree with you about the possibility of a cold solder joint. The OP said he used 22 gauge STEEL wire for the connection. Unless that's a misprint, that would be a cold solder joint. Trying to solder to steel or aluminum will not work. There may be a blob of solder on the joint, but it won't be bonded properly.
..... Bob
Beam me up, Scotty, there's no intelligent life down here. (Captain Kirk)
I reject your reality and substitute my own. (Adam Savage)
Resistance is not futile--it is voltage divided by current.
Cold solder joints and bad connections keep things from working and stop electrical flow! They do not force current through! Your problem is that you can't stop the flow. Your connections are perfect.
The best explanation is that the transistor/FET that controls the LED is not turning off firmly. Also, I like the explanation that the on-off transistor might be originally supposed to control an incandescent bulb and in the off mode a tiny current is left flowing, enough to dimly light the LED.
You might need to put a IN4002 diode in series with the LED such that the weak off voltage will not equal the minimum turn-on of the LED.
Richard
If I can't fix it, I can fix it so it can't be fixed
I remember having this exact same problem with some TCS decoders when they first hit the market. The only solution that worked for me was to increase the resistor size. With todays current crop of white LEDs, you can easily go up to at least 2000 ohms on your resistor and not really affect the brightness much. The added resistance will hold back that that minute current trickle and keep the LED from glowing.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
narrow gauge nuclear Cold solder joints and bad connections keep things from and working and stop electrical flow! They do not force current through! Your problem is that you can't stop the flow. Your connections are perfect...
Cold solder joints and bad connections keep things from and working and stop electrical flow! They do not force current through!
Your problem is that you can't stop the flow. Your connections are perfect...
I never suggested a cold solder joint was the reason for the LED staying on(i.e. forcing current through). In addition to the LED not turning all the way off he stated that it would go out if he squeezed the solder joint. That sounds like, in addition to whatever is causing the LED to not go out, he also has a cold solder joint.
I think the problem is that either Digitrax decoders do not handle LED's well or the cold solder joint issue using steel wire. I will solve this issue by either using a 2000 ohm resistor and using a different wire.
Where are you getting the "steel" wire from? Is it really steel or just 30 AWG hookup wire?
If it's actually steel then you will NOT get a good solder joint with just regular 63/37 lead/tin solder and flux. For steel you need special solder and flux formulation.
What are you using to solder the resistor to the LED lead? Is it a soldering iron? Soldering gun?
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
I am using 22 AWG hookup wire that is not threaded it my be copper or steel and 30 watt butane powered mini soldering iron. I tried a different LED with a thinner wire and the LED went off completely when I turned it off with the F0 function button with my Digitrax DT402D throttle.
alloboard I am using 22 AWG hookup wire that is not threaded it my be copper or steel...
I am using 22 AWG hookup wire that is not threaded it my be copper or steel...
alloboard,
I assume by the phrase "not threaded" you actually mean it's solid-core (vs. stranded) hook-up wire? I can guarantee you it isn't steel. Solid hook-up wire is generally tinned copper. (That's why it has a shiny appearance to it.) Stranded is copper-colored.
You can use 22 AWG wire but it's way overkill for what you are doing. 30 AWG is quite sufficient for the job. Also, it's usually better to go with stranded wire (vs. solid-core) for decoder installations because stranded wire is more flexible. You can only bend or manipulate solid wire so much before it fatigues and fails.
Last question for you. How long are you leaving the soldering iron on the LED when you are soldering the resistor to the LED lead? If it's a number of seconds? If so, then that might explained why the other LED failed.
You only want to heat up the part(s) just long enough to get the solder to flow. A little dab of flux paste will help the solder to flow evenly so that you get a nice bright, shiny solder joint.
I leave the soldering gun for a second technically! I tried a different LED with a thinner wire and the LED got dimmer when I turned it off with the F0 function button with my Digitrax DT402D throttle. However when I connected the rear LED light to the SDH164D and switched from forward to reverse on my throttle the dim front light get even brighter. I noticed that when I touch the white(-negative) wire the front LED goes off completely when I turn the LED off or switch to reverse. So what matererial can I use to simulate my finger as a substitute for conductivity. This is a picture of my decoder below.
I thank you all for for informative response.