I just heard from someone that Digitrax DZ123s have a history of this, in his experience and reputedly. That would explain a lot.
I have a fair bit of experience putting in LEDs, so they are in correctly, isolated, shrink wrapped etc. and I have the resistors in line correctly. And the resistors are from the same batch that has not given problems in any other install (however, there is a chance that 3 consecutive resistors selected out of a bag of 100 could be faulty.)
What I didn't make clear is that the locos were running for more than half an hour in each case with the full install....shells on etc. and normal LED operation. I was taking some time to set the CVs in the lighting style I desired on these road switchers. Then, with each, I powered down. Left and came back later. When I powered up, the LEDS popped.
I have only one other DZ123 in operation, and I haven't run the loco in a while. I should check it.
Meanwhile I am going to town to get some 1K or 1.2K Ohm resistors to see if they will do the trick.
I had two locos burn out LEDs once even though they had a 1K 1/4 w resistor in line. It turned out being a bad bach of resistors. Take some free advice and check your resistors first. Radio Shack sells them in a five pack for under a buck but the LEDs are three bucks each or more. Test and test again is my new motto. BTW I only use the 1K 1/4 watt and the LEDs work great. The clubs Lenz puts out 16 volts and my Power Cab puts out 14 volts but you cant tell the difference in the LEDs.
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!
Jeff But it's a dry heat!
davidmbedard wrote: What voltage are you dropping from? If you are running the Zephyr, you need to drop from 14volts, NOT 12.David B
What voltage are you dropping from? If you are running the Zephyr, you need to drop from 14volts, NOT 12.
David B
Thanks.
Which means? that I need more resistor?
I am thinking here that this work around is just because of this particular brand of decoder. I have never had a problem before I installed a few of these.
davidmbedard wrote: Is the OP sure he installed the decoder correctly? The Bachmann Baby trainmaster isnt the easiest install. You need to Isolate the decoder from the 2 halves and make sure that the orange and grey wires are not pinched in the frame. I suspect a faulty install rather than a light issue.In terms of lights, I just put the resistors I need on the colored non-blue lead (white, yellow, violet or green). I find that if I just put one resistor on the blue lead, the decoder doesnt like it when Ive got more than one light on at a time...David B
Is the OP sure he installed the decoder correctly? The Bachmann Baby trainmaster isnt the easiest install. You need to Isolate the decoder from the 2 halves and make sure that the orange and grey wires are not pinched in the frame. I suspect a faulty install rather than a light issue.
In terms of lights, I just put the resistors I need on the colored non-blue lead (white, yellow, violet or green). I find that if I just put one resistor on the blue lead, the decoder doesnt like it when Ive got more than one light on at a time...
Yeah, that's why I think its weird. I have done these split frames before and I have been careful with the motor leads coming through the frame and also isolating the motor points from the frame once I bend the tabs off and solder on the wires. The motor function has been fine on both anyway.
However, it doesn't make much sense, so I think I must have a problem somewhere with the install, so I am going to pull it apart and recheck/redo from Step One.
I have separate resisitors on the second install and it still popped the rear light.
Anyway, why wouldn't the resistor protect the LED? I have never had LEDs burn out after an install, in split frames or any other. I can't think why it should pop unless its the CV62 setting as noted above.
Vail and Southwestern RR wrote:What's the command station/booster?
Previous posts, he has a Digitrax Zephyr. so that rules out a voltage selection switch.
I would test any new decoder with your leds before installing it in your loco.
I just read up on this decoder. CV62, keep alive, has an effect on voltage applied. For LED CV62 must be set to " 0 ". CV63 should also be " 0 " if no ditch lights.
Ok, this is weird. Not only was there a hot spot on the first DZ123 and then no lights, but a second identical install just lost the function of the rear light, but the headlight still functions.
Why?---the rear LED in the second case is damaged. It won't light. I double checked the two non-working LEDs in the first install and they also are fried (in addition to the fried element under that decoders shrink wrap).
What would make the LEDs and or decoder elements "pop" off?
On the second install there are no shorts, pinched wires. None that I can see on the first either. On the second install I used a separate resistor for each of the white and yellow leads.
Now, here's the thing. The damage seems to be done when the power is applied to the track. That is, they do not "pop" in the middle of running.
I have used the 750 ohm 1/4 W resistors I always use with other decoders. Digitrax calls for around 680ohms. Am I too far off in the resistors? I don't think so.
Perhaps there is something in the throttle unit or somewhere on the layout giving a surge to the rails at start up. I will have to check around.
Vail and Southwestern RR wrote: I'm going to swim against the current, a little bit....One resistor in the blue line should be fine, as long as you don't split to the two LEDs until after the resistor. If both LEDS try to be on, the resistor will still limit the current, there shouldn't be any trouble.I think it is much more likely there was a short somewhere in the circuit, that took the resistor out of the circuit, hence eliminating the current limiting, and blowing out the drivers.
I'm going to swim against the current, a little bit....
One resistor in the blue line should be fine, as long as you don't split to the two LEDs until after the resistor. If both LEDS try to be on, the resistor will still limit the current, there shouldn't be any trouble.
I think it is much more likely there was a short somewhere in the circuit, that took the resistor out of the circuit, hence eliminating the current limiting, and blowing out the drivers.
Yeah, that could have been the case too.
Well, I'll be darned. Thanks, fellows. You just helped me figure something out.
The Resistor can go on either wire--the function wire or the blue common wire. That just makes sense as the resistor is in circuit either way---but one always has to put in two (which would always be the case on the function wires).
I have always put my resistors on the blue wire as shown by the Litchfield Station diagram wherein the circuitry for those "glowing" Soundtraxx decoders is shown. But I have always used two----on each part of the blue wire heading to each end of the loco.
This DZ123 is the first one that I thought I would put in just one resistor. Look what happened!
From now on I am going to put them on the function wires as shown in most manuals.
Dr. Frankendiesel aka Scott Running BearSpace Mouse for president!15 year veteran fire fighterCollector of Apple //e'sRunning Bear EnterprisesHistory Channel Club life member.beatus homo qui invenit sapientiam
See the Digitrax Decoder Manual for full details of wiring 12-16V lamps, 1.5V lamps, and LEDs. Lamps that draw more than 80 mA when running require a 22 ohm 1/4 watt resistor in series with the directional light function lead to protect the decoder.
Thiss link has info on LED wiring for Digitrax.
http://www.digitrax.com/ftp/decodermanual.pdf
My guess is you shot yourself in the foot, my friend
Well this Digitrax DZ123 is fresh in a Bachmann Spectrum FM H16-44 with new LEDs etc. etc. It always seemed to be acting oddly. It didn't seem to want to take changes in the lighting CV 49 and 50 very well.
After testing, I just put on the shell and returned it to the track. When I applied power, the lighting function of the decoder popped. Lights don't work, and there is a burned spot in the decoder shrink wrap. Never had that happen before, although I don't use too many of these type of decoders. (Train runs fine otherwise.)
The LEDs are intact.
I don't suppose it is because I used only one resistor on the two blue leads for the headlight do you? Should I really use a resistor for each LED? It just happened to be convenient to run both leads to one resistor and then to the decoder in this instance. Whattya' think?