Okay,
So I think I learned an important thing...the hard way. I know how a dcc unit will behave when the motor is drawing too much current...I think. There was a VERY important detail that I had forgotten until I fried another DCC board today. The DCC board did smoke as soon as I turned on the power. Surprisingly, however, it continued to run. And, as long as I ran the train in short stents...say...no more than ten feet, it continued to run well. So I did run the train, but it didn't even complete a full lap before the board burned up. I believe this is what the DCC board will behave like when the motor is drawing too much current. This is why. Today, I got my replacement boards in and I had changed to a newer motor in the locomotive that I started this thread about. The new motor ran fine on the DCC and I had no further issues with THIS locomotive. The old motor most likely would have burned the board up again, but the new motor had no issues...and interestingly, I didn't get a puff of smoke when I turned on the DCC power unit. However, I also wired up a IHC (AKA POS...at least this one was) for DCC. It did the exact same behavior that my Athearn had done. The puff of smoke...10 minutes run time...then a shorted out board that won't work anymore. I know I had the IHC wired perfectly. The frame and truck frames are plastic, so there is no way any shorts were happening with the frame. It was the motor. It just heated the board up until it melted. Does this sound right to you guys. Is this a motor drawing too much power? I think we need to make a list of motors that will fry DCC units or something.
Got to buy the correct LEDs. There are white, sunny white, and golden white. Plain white are bluish in color and best used in commercial structures to simulate flourescent lights. Sunny white LEDs look like modern sealed beam locomotive headlights, golden white (I use Miniatronics Yelo-Glo) look like incandescent bulbs used on first ggneration diesels and steam locos.
You need to know none of the details of the electronics, use a 1K resistor in series with each LED. Done. I can run through the theory if you like but the calculations will show that a 1K resistor is appropriate. LEDs are polarity sensitve, they don't work if hooked up backwards. But they don't blow up, either. There's a nice large picture on Wikipedia that shows what an LED looks like and which pin is + and which is -. The blue decoder wire is always +.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Randy, I am hesitent to switch to LEDs because of two things. 1, they produce a bluish white color that doesn't seem right for a train. Secondly, I go to the store and ask for a led and a resister for it, and I have to know the voltage, the wattage, the resistence needed, the ohms...I mean...I don't know any of that. What is the best LED/ resister combination that is best for most models of trains and what do I need to know to buy the right material? BTW, thanks for your help. It has been invaluable.
Absolutely not. The DCC signal is square wave AC, so half the time the black wire will have the opposite polarity of the blue wire. Since the blue wire comes outof the decoder after the rectifier, it would be a dead short across the rectifier - most likely blowing the rectifier which will render the decoder 100% dead.
For simplified light wiring in a Blue Box loco, you can leave the light post connected to the frame as it comes, and connect the other side of the bulb, the one that conencted to the old top clip, to the white wire. This results in what is called half wave lighting - the function wires on decoders are the grounds, so the alternating phase (poalrity) of the frame/black wire/rail is not a problem. The lights will not be as bright as if they were properly isolated and fed witht he blue and white wires because with half wave wiring they are only getting power on half of the DCC waveform (they are switching on and off at the DCC frequency, but since incandescent bulbs do not instantly turn off, it appears that they are on steady - just dimmer). I'm not sure how well special effects will work like this - like a Mars or Gyralight - my guess it not as good. For a basic on/off headlight it will work fine.
The RIGHT way to do a Blue Box is to get rid of that one giant light bulb altogether so there is no more campfire int he cab appearance, and use LEDs or micro bulbs to put the light source directly in the headlight lens so it lights up the headlight and not the entire inside of the cab. This is of course more involved and requires soldering on new function wires, and int eh case of 1.5v bulbs or LEDs, adding resistors to each one, plus figuring out how to mount them in place.
Why would you connect the blue wire from the decoder to the frame of the loco? The blue wire is supposed to go from the decoder to one of the legs of the lamp, either LED or bulb. The white or yellow is the other half of the circuit returning to the decoder. Appropriate resistors have to inserted in the circuit according to the decoder instructions and the current limits of the device that you are using for illumination.
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
Blue wire was cut off. However, I saw this guy doing a tutorial on how to install DCC decoders and he attatched the blue wire to the light frame. The blue wire is the common wire for the light, so, in theory, it should be able to go wherever the black wire goes, right? I was going to try using the blue wire, though I haven't used it in previous instilations. While I haven't used it yet, I am interested...can the blue wire not be connected to the ground (frame)?
You'd THINK the orange wire should go on top, based on the fact that the right rail is the one with the long tab on each truck that touches the top clip of the motor. That is, if short hood forward is what you want.
But, if it runs the wrong way even after the decoder is reset (CV29 is an EVEN number), then you have 2 choices, flip the motor wires or adjust CV29.
Instant smoke even before advancing the throttle tells me either part of the decoder was touching the frame, or an unused wire touched the decoder or frame, or perhaps you connected the blue wire to the base of the light bulb bracket - since that's connected to the loco frame and thus the left rail.
KevinsHope @ simon 1966 - How could the motor leads be flipped around? In the athearn trains, the frame that supports the motor leads is different on the bottom than it is on the top. I mean, I could attach the orange wire, which normally goes on the top of the motor, to the bottom lead, but that bottom lead.
@ simon 1966 - How could the motor leads be flipped around? In the athearn trains, the frame that supports the motor leads is different on the bottom than it is on the top. I mean, I could attach the orange wire, which normally goes on the top of the motor, to the bottom lead, but that bottom lead.
I don't know, perhaps you reversed the motor? Anyway, the how is less important than the solution. If you flip the motor leads the loco will go in the other direction when you select forward on your DCC throttle. Or as I said do it via CV, either solution will work.
BTW, I have had this exact thing happen to me where I was sure I had wired the motor correctly and the loco would always go backwards when forward was selected on the throttle. I use Decoder Pro, so for me the easiest solution by far is to simply change the forward direction via CV.
I meant, before I converted it to DCC, and then, after I converted it back to anolog. However, I have a jumper that I use to get it to run in DC mode on a DCC track. EZ command lets you run one anolog train on F10, but its not that great. It has constant current through it, so the motor hums and the train moves slowly, so I don't really use that feture very often. Anyway, presently, I have removed the DCC wiring from the train, so it is anolog.
KevinsHopeNot to be dence here, but...if the engine had a short somewhere in it, wouldn't it have problems when being used in anolog?
One thing that has really been bugging me about this locomotive is that it reverses polarity when you put it on a DCC track. What I mean is...on a DC track, if it goes forward, then it will go in reverse on a DCC track.
I tried reversing the trucks, but this just reverses the direction it goes in on both DC and DCC tracks. So..it still flips polarity between the two. None of my other Analog engines that i converted to DCC did this. They all went the same direction on both DC and DCC. Is this something to be concerned with? Is this possably a sign of a short? BTW, it does it, even if I run it in analog mode on the DCC track. It still reverses polarity. Anyway, if there was a short, wouldn't the short still be apparent in analog mode?
It just means that you have the motor leads flipped. You can either manually change them over, or edit CV's to change the normal direction of travel.
Not to be dence here, but...if the engine had a short somewhere in it, wouldn't it have problems when being used in anolog? One thing that has really been bugging me about this locomotive is that it reverses polarity when you put it on a DCC track. What I mean is...on a DC track, if it goes forward, then it will go in reverse on a DCC track. I tried reversing the trucks, but this just reverses the direction it goes in on both DC and DCC tracks. So..it still flips polarity between the two. None of my other Analog engines that i converted to DCC did this. They all went the same direction on both DC and DCC. Is this something to be concerned with? Is this possably a sign of a short? BTW, it does it, even if I run it in analog mode on the DCC track. It still reverses polarity. Anyway, if there was a short, wouldn't the short still be apparent in analog mode?
KevinsHopeI have a voltage meter, but it doesn't test for shorts as far as I know. I know how to use it to test for a complete circuit, but I don't really know how to use any of the other functions. Maybe it can test for shorts.
Take the locomotive and remove the prior fried decoder. Touch one lead to the frame then:1. Touch the other lead to the truck power pickups. If the reading goes to zero there is short. 2. Touch the other lead to one side of the motor. If the reading goes to zero there is a short. 3. Touch the other lead to the other side of hte motor. Once again if the reading goes to zero there is a short.Move the original lead to the truck power pickup wire and retest the two motor leads.
That should show up where any basic shorts are in the chassis.
If there are none it has to be the current draw of the motor. But that doesn't explain the 3rd one that fried without applyin power. Also remember that some motors spike the current draw when first started. Flywheels will magnify this effect. I had a proto-2000 PA unit that had a stall current of only 350 ma. Looks really good on paper. The catch was it spiked to 3A ( 3000 ma ) on start up. Fried a few decoders before I figured that out.
It is the first of the two. However, I replaced the screws with rubber attatchment units, which, incidently, fit perfectly in the holes. It may also be relevent here to state that I added some small fly wheel motors off of a spare motor that I had lying around. i don't think that would make a difference, but it might. Other than that, it is identical to the one pictured in your first link.
What exactly does your SD-45 look like inside? If it is this one, http://www.hoseeker.org/assemblyexplosionAthearn/Assembly%20Explosion%20Athearn%20SD45%201965.jpg, there are metal screws that attach the motor. These will cause a short.
If it is this one, http://www.hoseeker.org/assemblyexplosionAthearn/Assembly%20Explosion%20Athearn%20SD45%20SDP40%201973.jpg, then there is normally a bottom clip which has some metal tabs that extend down past the rubber mounting holders and contact the frame. These will also cause a short unless removed.
The best way to test for current draw is to place the loco on a track and use a DC power supply. Put your current meter in series with one lead between the power supply and track.
Turn the throttle to max and hold your loco with one hand. Don't hold the loco still but slow it's movement by at least half. The meter will show the current. If it shows negative or the needle deflects the wrong way, reverse the meter leads between the supply and track.
Springfield PA
I have a voltage meter, but it doesn't test for shorts as far as I know. I know how to use it to test for a complete circuit, but I don't really know how to use any of the other functions. Maybe it can test for shorts.
Definatly time to get a small digital voltmeter that can also check for shorts. Radio Shack has a nice simple digital one, reads both AC and DC voltage, ohm's and continuity or the ablity to check for shorts. You set it for this settting and if you touch the red and black leads together it beeps. So you touch one lead to one motor bruch and one to the frame/wheels/trucks and see if it beeps, do the same for the other motor brush. You can also check for shorts in the wheelsets, between the trucks and the frame ect. The older metal trucked Athearns pull better in my opinion and I have several with TCS decoders in them without any issues. My guess if its not a short, which is probably is, then the motor draws to much. However as stated above, if the decoder goes "poof" instantly, its most likely a short. Make sure you cut off the copper spring tabs that stick down from the bottom brush holder as those can easily cut thru electrical tape and create your short circuit. This is my guess as to whats happening, espicaly if the SD45 ran fine prior to putting the DCC in the engine. All of my older Athearns are still running their slate grey "ring magnet" motors. I do go thru and clean/relubricate them, add thrust washers to the shafts if they "walk" back and forth to much. I also evaluate ench engine on DC at the local club layout that has meters on every cab. We have both voltage and Amp meters so I can see how the model performs prior to installing DCC. I have had to replace very few Athearn motors, and the ones I have were obviously having issues either with vibration from bent armatures, bad flywheels or overheating from weak magnets/age related issues. Mike
LHS mechanic and geniune train and antique garden tractor nut case!
KevinsHope The next chip fried the minute I turned the power supply on. I actually watched the smoke roll away from the chip.
The next chip fried the minute I turned the power supply on. I actually watched the smoke roll away from the chip.
I think that this is an important piece of information. If the loco was simply placed on the track and the power was turned on and the decoder fried without any attempt to select and run the loco, then surely this points directly at a short in the installation? The motor should not have been drawing any current at this point. To my mind if the current draw of the motor was the issue, this would have fried the decoder once it was selected and being run.
The first thing I would do in this instance is to remove my wiring and use the Ohm setting on my meter to check for shorts in the basic mechanism.
First, place one meter probe on one of the motor contacts, place the other on the chassis, you should see infinite resistance (open circuit), keeping the probe on the motor contact move the other to each wheel set, and so on around the loco. If you ever see 0 ohms there is s dead short between the motor contact and the point at which you are measuring. Do the same for the other motor contact..
Then do the same for the wheel pick ups. There should be infinite resistance between the left and the right wheel pickups. Using a meter in this way you can identify the conduction path from the left and right side pickups and also verify that they are completely isolated from each other. Hopefully you will also find the source of the short.
I concur, you really need to get a basic meter so that you can check for shorts. Also, what DCC system are you using? Does it have a low current program track? If so, that is a safe place to try and read and write CV's to see if the installation is correct.
I agree with Randy in that it is likely too much current draw. Those older locos had motors that could draw some amps. You will need a meter that can read at least up to 3 amps to be safe. Mine I think goes up to 10. Read the meters instructions as it will tell you how to set it up, probably with a diagram. I do a current draw(amp) test using a DC power pack. The meter goes on one side between the track and power supply.
If it were me, I would just replace the motor with a new can type which will be more efficient and quieter.
Richard
I had the motor secured with the rubber holders. One thing you said that I can confirm is that the motor has slate colored sides, so it may be the older Athearn motor. If the current draw was too much, then would that fry the DCC chip? Is there a way for me to test how much current it is drawing...and...if you answer this, pretend like I'm a dummy with electrical stuff. I have a meter, so I might be able to test it, but I would need some understanding on how to do it.
Metal sideframes? That IS an old one. They pick up differently than the versions people refer to as "Blue Box" models. It may in fact only pick up one one side of each truck. The last one I saw like that was a Trainmaster, and I don't remember exactly how it was different other than the metal sideframes. If you truly have the motor isolated from the frame - with no decoder check for continuity between either motor brush and either rail - it must be completely open. That old, it's probably not th gold color motor - if it's the black sided one, or the even bigger older motor, your problem is probably too much current draw, if it truly is isolated. Is it the motor drive that's burning out, because the only way that can happen is a)motor draws too much current b)motor leads are shorted or c)motor leads come in contact with track power. Verify with a meterIf the motor is compeltely isolated fromt eh frame, it should not matter if track power is inteh frame - you siad you put tape down, how is th emotor fastened in? On the newer ones there are 2 plastic/nylon clips that hold the motor in place. If this one uses screws, you need to use nylon screws instead of the metal ones or you are just bypassing the tape you put on the motor.
Hello All,
First post. So, I have an OLD Athearn anolog SD 45. I LOVE this model locomotive. But it has cost me four DCC chips so far. Before I go any further, I should say that I also have a GP9 and GP50 and I was able to add the same DCC chip to both of those with no issues. However, with this SD45, something is frying these chips, and I can't figure it out. I have I had my black wire grounded to the frame via the headlight bracket. I have the red wire to the front truck, and a conection wire from that truck to the rear truck. I am using the white wire for the headlight, and then, of course, I have the orange and grey wires connected to the top and bottom brass strips respectively. I isolated the motor with electric tape from the frame. After burning the first two chips up, I reasoned that there might be a problem with the trucks causing a short. The truck frames are metal and the covers for the couplers are metal, so the two were causing quite the spark when they touched on the turns. I painted the entire bottom of the frame with acrilic paint, which, when dry, is non-conductive. The next chip fried the minute I turned the power supply on. I actually watched the smoke roll away from the chip. I can't figure it out. What am I missing here? Is it the ground wire atatched to the headlight bracket? If anyone has any ideas, PLEASE help! I don't want to run this as anolog on my DCC track. Thanks in advance for your thoughts.