# Baldwin Centipedes strange behavior on DC at startup



## parandyb (Mar 3, 2014)

I've got a pair of Paragon 2 Centipedes running on my DC layout and am seeing strange behavior at startup. I have a DC master and am trying to program my way out but so far no dice. I'm wondering if the consisting programmed into the units is behaving strangely because they are on DC power. When they start up they begin to move in erratic little steps. They move about a half inch and stop and repeat this sometimes four or five times before they start to move smoothly. Please don't tell me this is dirty DC power, because these movements are in perfect synchronization and the exact same length of time each time. And as this is happening the cab lights on the two units are flashing in perfect synchronization as well. I find it highly unlikely that dirty power could make them behave in perfect synchronization while on different parts of the track. 
I have tried BLI customer service who blamed it on dirty DC Power but they also blamed some other behavior on dirty DC power which turned out to be due to the lead and trailing trucks not screwed down completely and lifting the powered wheels off the rails. I downloaded the 192 page "Paragon 2 Diesel Technical Reference Manual" off the website and have been studying and tinkering cautiously but so far not able to resolve this one. Anyone else seen this strange behavior and know how to deal with it?


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## Brakeman Jake (Mar 8, 2009)

Based on your description of the problem,I believe one of your locos has a defective motor wich actually disrupts (shorts) track power when rotating slowly,the shorts not being long enough to show as speed increases.A spotty armature can do this.

One quick check is to install a small bulb across your tracks and see if it blinks when the problem occurs.If it does,try running your locos alone to determine wich one does this.Run them at creeping speed for this problem to show,and it may take a few trys at it.

I'm guessing here...but that's what I'd do first off.This failing,we'll look deeper.


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## parandyb (Mar 3, 2014)

*Possibility!*

That is a much more likely response than I got from BLI. 
Actually I have volt and ammeters attached and I have been wondering why I'm getting a very high current spike when this happens. The Ammeter is swinging between 1 and 4 amps during this period, and it may be it is showing me a short that resolves so quickly it wasn't registering with me as a short. I'll check this out. Thanks for the response.


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## parandyb (Mar 3, 2014)

*Sounds good, but then again--*

Tried the two locos independently and while the more I look at it the more the behavior of the meters could indicate an intermittent short, I doubt if that is what is happening because the two locos do exactly the same thing when run independently. With only one on the track the ammeter is swinging between about .5 and 2 amps which is about half what it was with both on the rails. Also, the swing of the ammeter continues at about the same pace after the loco starts moving normally and the cycle period of the swing doesn't change even as the loco gathers speed. It seems more like the swing in the power draw is more about the sound system. I can see that the sound system in these takes a lot of current to power because I get quite a jolt off the ammeter when the sound system starts up. What is strange though is that the amp draw remains constant until the motor starts to move and then the current swing begins. I have tried raising Vstart a bit to quickly get it over this jerky start but that just results in shorter jerks and a less prototypical looking speed curve at start up. I can tell that this current swing is affecting the available current to the motor because I get a lot of brake squealing during the start up. Apparently the motor is revving up and down because of the current drop. I might suspect the power supply can't handle them but this thing at full throttle puts out over 5 amps at 14 VDC so I should be ok there.


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## Brakeman Jake (Mar 8, 2009)

Another guess here...sound units do draw considerably indeed and are usually set to require a minimum voltage in DC mode.The sound unit startup voltage may be set a little too low so that sounds rise when track voltage and amperage are too low to support them.

CV131 should be set at 72,but then it may be too low for this particular case.If reading is lower,I'd correct it.If CV131=72,I'd try raising it somewhat to see if it changes anything.


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## Brakeman Jake (Mar 8, 2009)

Take a look at Paragon 2 Tech. Ref. manual (release 1.04),pages 14 & 15...I don't understand all there is,but I believe the answer to your problem is there.


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## parandyb (Mar 3, 2014)

*Are these DCC manuals written to make them confusing?*

Yeah Jake, I hope you are right that my problem is somewhere in pages 14 or 15. I have those almost memorized at this point but I don't completely understand it either. And I have a degree in Chemistry and a minor in Physics including courses in Electricity and Magnetism and Instrumental Analysis.
It doesn't help that the editing of that manual is so lousy that it contains such gems as the Bolded Note on page 27 that says-"CV2 must be smaller than Vstart and Vhigh". Since CV2 IS Vstart this is pretty hard to pull off. LOL! I think they meant smaller than Vmid and Vhigh but there are typos all over the place. I think the manual needs a data dictionary. Vstart is the motor speed at step one and Vmin defines the track voltage that applies the lowest or starting motor power. It sounds to me like that is a conflict.
I have been suspicious about the relationship between the sound system and the motor just like you are. The first thing I did was reset CV133 (Master sound volume) from 128 to 60. It seemed like these things were screaming and I figured I would need less power for less volume. I'll try setting the the sound system and the start point both higher and see what happens, but the sound system isn't restarting so that would seem to say the value is high enough. This tremendous current swing that is so rhythmic is really confusing me because it is so consistent at any speed and my other BLI locomotive doesn't exhibit this behavior. 
At least since no one has jumped in here saying they have seen something similar I'm getting suspicious that the problem is either that these locomotives aren't at their factory settings or that something is really wrong inside there somewhere. If this doesn't work I may try resetting to the factory defaults. Maybe someone played with these before I got them. :dunno:


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## Brakeman Jake (Mar 8, 2009)

The locos being tinkered with before you got them is a remote possibility,so resetting isn't a bad idea,short of any success otherwise.

You say you have a fine running BLI loco...can you actually read CV's with your setup?If so,reading the suspicious CV's from this one and duplicating them to the other may work.

Other things I'd try...
Set CV29=54...ignore CV's 2,5 & 6...may be these locos would be happier using the speed table.
CV19=0...consisting de-activated
CV10=0...BEMF off...this feature may complicate life setting up a loco.While consisting,may have locos fighting eachother.I don't know if it works in DC though.


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## parandyb (Mar 3, 2014)

*Does consisting involve the locos talking to each other?*

He Jake, if you are still following, and anyone else for that matter. Do you know if consisting involves the locos talking to each other or just the control unit sending signals to each? They use the word controller and I'm not sure if they mean the controller in the loco or the base unit. Unless the locos talk to each other I don't see a point to DC consisting at all. You can achieve all the other functions with other CV's the way it looks to me. Not that I'm an expert with DCC. Or even a novice for that matter. LOL

I was under the impression that Centipedes sold as AA pairs were programmed for a consist, but the tech manual says the initial value for CV19 is zero and the operations book says they are 'WIRED' for consisting in DC and no programming is required. That word 'wired' can't possibly mean what it sounds like but this seams to indicate consisting is already off.

And to answer your previous question, it appears the DC master is not showing me the current CV settings, only what I am programming. So I guess it is time to keep a record of what I am doing. BTW, I did reset the defaults with no change. Whatever is going on is not the result of program hacking. I also tried setting up the voltage to start the sound system and the Vstart voltage by about the same amount and that doesn't alter the swinging ammeter. I even began to wonder if the momentum in my throttle electronics was the culprit but I tried running these without momentum at all and they of course respond quicker but they still have the startup jerks and amperage swings. I'll try using the speed table and see how that goes.


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## Brakeman Jake (Mar 8, 2009)

Would you try running your locos with straight DC? I mean without the DC Master just to see what happens.

Although you have enough power coming off your power supply,I suspect the DC Master may have a hiccup trying to power two large locos,wich yours are.All infos I could gather points to the operation of a single loco,the DC Master not being able to send different instructions to different locos so letting enough power to flow through it to get multiple 
locos started may have been an oversight to its designers.

The only possible consisting that is available to you now is tuning two locos to react similarly to DC power,put them on the track and turn the throttle...no independent control of either function on only one of the locos.

Consisting with DCC is another world.You can program two locos with different adresses to respond to a common adress (Consist adress) when they're together and still have a temper of their own when solo.

Then,with a little fun work,you can program their individual decoders to behave differently under consist control,like one sounds the other silent,only the leader turns its lights on,etc.

Under consist,the locos don't talk to eachother,they simply react differently (as per programming) to a single command from the power station.You don't have to think about it,it becomes automatic as long as you consist the locos the same way (leader-trailer).Then separate them,dial their specific adress and they resume normal operation as solo units.

With all that said,I believe you have reached a point you should consider DCC.You have great engines on hand and you could really enjoy them,at least far better than the DC Master will ever let you.And my personal note...if you decide for DCC,don't go with the bargain sets...you'd turn around in circle with plenty of limitations.


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## parandyb (Mar 3, 2014)

*Trying different power supplies*

I've now tried everything we have discussed except the speed table and turning off BackEMF which I'll get to today. These units have been run without the DC Master. In fact I only bought it when I couldn't get rid of this weird startup situation and thought maybe programming would help. 
However they have only been run with one power supply. Don't know why I hadn't moved them before but I have five different power supplies on the layout so I'll try them on some of the other parts of the layout.
I'm getting more concerned all the time that I'm not going to be able to resolve this. As a test I ran one of them light on my large mainline loop to see what would happen when it gets up to a significant speed. I was surprised to find that this constant swing in amperage continues even with the locomotive running at a pretty high speed. So whatever is going on never resolves even when it has full power applied. The fact they both do this even when alone on the track but no one else is reporting such issues is leaving me with few new ideas. At this point I'm hoping against hope that there is something in the track or wiring causing it and it will disappear when I move the locos to another part of the layout with a different power supply, but I've got about 40 locomotives on the layout and I'm not having this problem with anything else so that seems like a pretty remote possibility. Oh well, they will look nice at least. :dunno:


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## Brakeman Jake (Mar 8, 2009)

Indeed,ideas are getting in shorter supply.Do you know anyone who runs true DCC who would allow you to try your locos on his layout?Better still if this someone can read and possibly print (Decoder Pro) the CV's.I'm very suspiscious that DC Master does program right and since you're programming blind,you can't verify.

If they run well on DCC (with CV29=34 or 50),that would rule out any mechanical issue like binding gears or whatever.

Having both locos behaving same tells me it's not the case,but at least we'd be sure.

I'll try to find the default settings for these locos then check if Decoder Pro has anything on these.If I find anything I'll let you know.


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## parandyb (Mar 3, 2014)

*SUCCESS--I think.*

Jake, the scientist in me is reticent to declare a problem solved too early, but I believe the light I see at the end of the tunnel is not a T1 bearing down on my Centipedes. 

It looks like it was the BackEMF that was the problem. When I turn it off on both engines, the flashing cab lights and jerky start goes away. Initially they wouldn't start at all. They sat there revving their butts off and not moving. If I would nudge them with an 0-5-0 switcher they would move a bit but stop again. I decided maybe I could resolve that with the Kickstart and it looks like I can to some extent. The Kickstart CV was set initially at 40. I kept bouncing it up until I got it up to 160 and now they start on their own and have incredible slow speed control. The problem is that hooking them up to a sizeable train negates the effect. The kickstart is obviously smoothing down too soon for them to overcome the inertia of the train. But I'm pretty certain a little creativity with Vstart and the control range will allow me to get them moving to a speed that by the time the kickstart smoothes off they will have overcome the inertia.

I'm not sure why the BackEMF was causing this, but I know from my college days that this phenomenon is actually caused by the rotating motor and would generate a magnetic field working against the direction the motor is turning. They can't possibly create this effect or turn it off so they must be electronically dampening the voltage being applied to the motor. Apparently that algorithm is actually causing the voltage to rise and fall in a cycle for a short time at startup. So the cab lights are flashing because they are fluctuating above and below the voltage for them to shut off, and the amperage draw of the motor, the lights, the sound system, etc. must have been causing the jerks. it is likely that the momentum in my throttle coupled with the very slow speed changes at startup from the decoder were complicating this.

In any event I can still turn up the kickstart to a max of 255 which is almost twice what my last test was and if I play around at the bottom of the control curve a bit I think I have this licked. If I get everything smoothed out I'll post a final note. In the meantime, thank you for your support here. Having someone to discuss it with that had ideas and didn't dismiss my problem as simple dirty DC power was a godsend. 

Wait till I get back to the guy at BLI that told me this had to be dirty DC power. :cheeky4:

One more thing. You suggested a bit earlier in the thread that I move to DCC. Time for me to come clean. I'm 62 years old and have been working in Information Technology for 40 years. I'm currently a consultant and expert witness. The last thing I want to do with my free time is play with computers. The trend in the hobby is not a positive one for me. I would much rather have spent the last week or two finishing the re-power project on my old Brass Gem Pennsy B6 switcher than playing with this DCC decoder. But I do understand the fascination most people have with the electronic gadgets today. 
Thanks again for your help. I'll let you know if I get this solution perfected.


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## Brakeman Jake (Mar 8, 2009)

If Kickstart does get the locos started,you've pretty much reached what KS can do for you.KS (in DCC) only works with the first klick of the throttle knob.Now,you'll have to tinker with CV2 until the loco actually keeps going slowly with a load after the KS effect has faded off.

The purpose of BEMF is to keep loco speed constant wether it is climbing or going downhill,either adding voltage to the motor or pulling back depending on the needs.It's known to cause weird effects when teaming locos as they sometimes kind of fight eachother.Then if you like to control your train manually,you don't need it either.Anyways,all basic CV settings should be done with BEMF turned off.It can always be re-activated later if desired.

Not that I want you to feel bad about it,but running your beauties on DC doesn't allow you all the wonderful sound features these decoders have.Since you already have a large roster of DC locos,I get your point though.

Coincidence,I too am 62 but have no degree whatsoever.I've spent forty years in automotive (mostly trucks and heavy equipment) and have tinkered with DC a lot,mostly without schematics on hand looking for shorts,etc.I'm now physically disabled so for me computer is a good way to keep the mind gears rolling.

However,I've always liked challenges and your problem was one I couldn't help but put my nose into it.How successfully?Time will tell...have a good day.


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