To get started in DCC, I bought a Digitrax Super Chief set w/DT400R throttle and a Bachmann On30 Davenport Loco. The loco ran great on DC.
1. Then I installed the Super Chief, and everything seems to work fine, except the loco runs much worse on DCC than it did on DC, especially a low speeds. It seems like the motor is "cogging" and about half the time it won't even start without a physical push. I have repeatedly cleaned the wheels and track with 91% isopropyl alcohol, but to no avail.
2. Another "DC only" loco continues to run fine on the same track using the same Super Chief setup, but changing to the right hand throttle knob set at 00 for analog. I tried running the Davenport on the right hand throttle, thinking it would revert to DC operation, but it doesn't respond at all.
I'm lost. Any and all help, explanations, suggestions, etc. would be appreciated. Thanks.
- Harry
When you say the loco ran much worse on DCC, does the loco have a decoder installed? Or are you running it in the Digitraxx DCC mode on address 0? If it's the later, not all DC loco's can handle the pulsed signal.
Springfield PA
Harry,
Does the Davenport have a factory installed decoder in it, or are you running it on 'Address 0' ? Most Bachmann 'DCC On Board' engines have a low end Lenz decoder that is marginal. By default it should be programmed to Address 3. Trying to run it at Address 0 will not work.
If is does not have a DCC decoder installed, and you are running it using 'Address 0' - You may be damaging it. Some motors have no problem with this, but others will perform bad and may be damaged.
There are CV's that can be 'tweaked' to improve the starting voltage, but that is another learning curve you really do not want to investigate right now.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
It is often the case that cold and new engines need more voltage to get them underway. They wear in and get smoother quite often...not always. Also, as any one engine runs for a bit, and the innards warm and lubes flow, they get quieter, smoother, and will start moving with less voltage.
Enter Ops mode programming, assuming you have the engine with a decoder, and fiddle with the value entered in CV2 which is "V-Start". It is the initial voltage assigned to the decoder's motor output upon the first speed step dialed into your throttle.
First, of course, make sure the engine is active on the DT400. Click the encoder knob to get the flashing icon, and then enter Ops Mode, CV2, and start with a value of 30. Exit, move the engine. No go on speed step One? Ops Mode once more, try 40. At some point the engine will move on the first speed step. Ideally you don't want it jerking into a 5 mph scale speed or higher. You just want it to start rolling slowly. Hopefully smoothly, but it may not be possible if your decoder has no BEMF control.
-Crandell
Thanks everyone. I should said that the loco has a factory installed DCC decoder. Bachmann advertises that it will run on DC or DCC, and it does. I guess I just expected in to run smoother on DCC than DC, whereas the opposite is true. On DCC it runs like the track is very dirty, which it isn't.
Crandell, I'll try the CV changes you mentioned, but on numerous occasions I tried turning the throttle wide open with no response, so is it likely that the CV changes will help?
Also, the loco is set for address 03 for DCC. It will no longer run on DC, although I suppose it might if I removed all the DCC stuff from the power supply chain. EDIT: I just tried that, and it still runs fine on DC.
Maybe it needs more break in time - it probably has less than 10 minutes total. Or maybe this is what I should expect from a very inexpensive decoder. I'm really more concerned about whether I should switch to DCC at all than I am with this particular loco.
HarryHotspurI'm really more concerned about whether I should switch to DCC at all than I am with this particular loco.
The mixed DC / DCC scenario always causes problems. Check the manual for the decode in the problem locomotive and see if it has the option to turn off DC mode all together. Often this is CV29. If that doesn't help it can always be turned back on.
I would dump the DC use with the DCC loco's and even turn off DC control in CV29. When set up right the DCC will run much better than on DC.
Bachmann - that answers it. The decoder Bachmann supplies for those DCC on-board decoders is a rather poor one, akin to the decoders you got when DCC was a new thing 15 years ago. Two things greatly improve Bachmann DCC performance: a better quality decoder and removal of the rf supression capacitors they now include on all locos - they interfere with the DCC decoder control of the motor.
DCC does need clean track and solid power - no different really than DC. When testing these locos under DC, is it on the same track with the DC supply connected in place of the DCC system? How big is the layout? Even a simple 4x8 oval needs more than one set of feeders to the track - especially if sectional track without soldered rail joints is used. The loco may run great on a single 3' piece of flex track with a pair of jumper wires connecting to it. That doesn't mean it will run with no power issues on the full layout.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
DCC can be a little scary and confusing at first but once you get a handle on your system and start operating multiple trains in different directions and different speeds, it is worth the frustration at first. As been referenced above, good decoders and a good locos make all the difference. I run all digitrax decorders except for one engine that came from Atlas with sound installed and I believe it has QSI decoder. and they all run like champs.
Texas Zepher replied on 10-08-2010 2:20 PM HarryHotspur: I'm really more concerned about whether I should switch to DCC at all than I am with this particular loco.I would have expected that question to be asked before a top of the line wireless DCC unit was purchased. How large is your fleet? My contention has always been that as soon as one introduces that second locomotive DCC just got to be the better choice.The mixed DC / DCC scenario always causes problems. Check the manual for the decode in the problem locomotive and see if it has the option to turn off DC mode all together. Often this is CV29. If that doesn't help it can always be turned back on.TZ - That’s the best approach, no question. But what I did was hopefully not as irrational as it sounds. I read everything I could find on DCC since almost the day it was invented, and when it seemed that the technology was mature (i.e. I didn’t want to buy a Beta video recorder), I narrowed my choices to Digitrax and NCE. Then I drove 100 miles in opposite directions to try them out. Of course the demo versions at the two dealers ran beautifully. For whatever reason, I chose Digitrax. I also knew that I had to have RC control, because I loved it. Logic might indicate that I should have bought the entry level Zepher system, but when the cost of RC was added in, the difference in price didn’t seem to great.I also bought four LenzGold JST-WH decoders which I have yet to install because I haven’t learned how.Before I did anything else, I saw and bought the Bachmann Davenport new, on sale for $23 with DCC included. I figured I had almost nothing to lose, because it was barely more than the cost of a decoder itself. The loco doesn’t fit the era I want to model, but I though it would be easier to learn DCC that way, and I could re-sell the loco if need be.Anyway, that was my thought process which lead to an apparently wacky decision.I admit I did not realize there was so much difference between decoders, other than features.What would really be helpful is if someone could link me to a sight explain in very basic terms how to install a decoder. I read a lot, but I still don’t understand how to tell if I need to worry about the motor being grounded to the frame, and what to do about it.BTW, my fleet is very small - the Davenport, two DC Bachmann Porters, one DC Bachmann Mogul, and one Fleischmann DC 0-4-0, which is Oe and not On30, but still I like it.HamltnbluePosts :2,435Joined: 05-05-2008 Re: RE:Two questions about DCC from a newbieHamltnblue replied on 10-08-2010 3:02 PM I would dump the DC use with the DCC loco's and even turn off DC control in CV29. When set up right the DCC will run much better than on DC.I tried that, but I’m not sure I did it right. Nothing that came with the loco had any info about CV, but somewhere on the internet I read that I should change CV#29 to 38. I did, and it ran much worse. So I changed it “back” to 34 (as the article said) and it wouldn’t run al all. Then I rebooted the whole system (if that’s not a proper MR term, I mean that I turned everything off and them back on. So now I’m back to where I started, except maybe a little better off as stated below. I’m not at all sure the CV#s were correct. Top 25 ContributorrrinkerPosts :9,351Joined: 02-14-2002Reading, PA Re: RE:Two questions about DCC from a newbierrinker replied on 10-08-2010 3:15 PM Bachmann - that answers it. The decoder Bachmann supplies for those DCC on-board decoders is a rather poor one, akin to the decoders you got when DCC was a new thing 15 years ago. Two things greatly improve Bachmann DCC performance: a better quality decoder and removal of the rf supression capacitors they now include on all locos - they interfere with the DCC decoder control of the motor. DCC does need clean track and solid power - no different really than DC. When testing these locos under DC, is it on the same track with the DC supply connected in place of the DCC system? How big is the layout? Even a simple 4x8 oval needs more than one set of feeders to the track - especially if sectional track without soldered rail joints is used. The loco may run great on a single 3' piece of flex track with a pair of jumper wires connecting to it. That doesn't mean it will run with no power issues on the full layout. --RandyNow how did you know all that stuff about my layout? (grin) It’s not really a layout yet, more like a test track to see what works and what doesn’t. Yes, it has non-soldered sectional track and only one feeder. It’s just and over an under loop about 20 feet long in total. Power supply is five amps, so I think that’s okay. I was testing near the connection, thinking that would avoid any power problems, but maybe electricity doesn’t work that way. I did crimp the sectional connectors a bit tighter, and darned if that doesn’t seem to have helped. Thanks.If you could point me to a site that explains to an electrical dummy like me how to install the Lenz decoders, that would be a big help. Eric97123Posts :178Joined: 02-10-2010Hillsboro, Oregon Re: RE:Two questions about DCC from a newbieEric97123 replied on 10-08-2010 5:23 PM DCC can be a little scary and confusing at first but once you get a handle on your system and start operating multiple trains in different directions and different speeds, it is worth the frustration at first. As been referenced above, good decoders and a good locos make all the difference. I run all digitrax decorders except for one engine that came from Atlas with sound installed and I believe it has QSI decoder. and they all run like champs.Thanks. It has now become obvious to me that I just didn’t appreciate the difference between decoders. I’ve heard that Digitrax, Lenz, and TCI (?) are all good. What’s your opinion.I really appreciate everyone’s thoughts and advice.
Aside from the decoders relatively basic options, it should still run the loco as smooth as it does on DC. DC on this engine has to go through the decoder too.Not sure what you meant in your first post. Just in case, don't ever have DC and DCC connected to the track at the same time. Running on DCC adddress 00 is not the same thing as running with DC power.
First. Check to see if the "status" of address 03 is set for 128 speed steps. When you select address 03, you should see "Stat=128" on the DT400R display. If you see Stat=128, that good. If not you will need to status edit the address to 128. See the Super Chief manual somewhere around page 80 for instructions.
Next, set up a programming track and try reading some CV's. Read CV29. If the address is still 03 then CV29 should be either 006 or 002. 006 allows the engine to run on DC as well as DCC. 002 disables DC so that it will only run on DCC. Any other setting at this point will not work. Try running the engine on your test track using address 003.
The value of 38 or 34(DC disabled) will work only if the decoder has been reprogrammed to a long address. (128 thru 9983). Until a long address has been programmed, 38 and 34 will have no effect and it won't run at all on DCC. Once a long address is programmed, CV29 should be changed to one of those two values to "activate" the long address. Pressing the Y/+ button at the prompt after programming a long address will program CV29 for you.
Here's a link I found to some info on that Bachman engine
http://www.girr.org/girr/tips/tips11/on30_davenport_tips.html
As far asdecoder installtion instructions try googling something like " decoder installation in xxx" ; xxx being the model, will usually find some info.
Martin Myers
I run N-Scale and have the same system and throttle as you. It is a great system for any level you take your layout to.
Stop trying with the engine you have as at $23.00 I would think it was not made to be good on DCC.
Get something good, such as an Atlas, or Kato. I have both.
Ken G Price My N-Scale Layout
Digitrax Super Empire Builder Radio System. South Valley Texas Railroad. SVTRR
N-Scale out west. 1996-1998 or so! UP, SP, Missouri Pacific, C&NW.
Lake Get something good, such as an Atlas, or Kato. I have both.
I don't think he can get an Atlas or Kato. He's running On3 scale. Besides, he got one heck of a deal on that 0-4-0. It's list price is $120.
That decoder is not that bad but the extra capacitors Bachmann puts in can run havoc on some stuff or combinations of stuff, get rid of them and then see if you still have a problem.
The capacitor is usually in the motor output circuit. It should be near where the motor connects to the board and will be parallel across the conductors.
There's nothign wrong with the Bachmann mechanisms, particularly their steam locos. They are generally good and smooth runners.
Removing the capacitors will help even the Bachmann DCC decoder - but it really IS that bad. No silent running, no BEMF, no support for start/mid/max or speed tables. Etc. There's a reason you can get a loco that cheap witht he decoder already installed. Look how much they actually charge for those decoders if purchased seperately. You can get a far superior decoder from NCE for a lot less than that.
Their locos with sound included use Tsunami decoders - those are good. The non-sound Bachmann decoders though - just say NO.
rrinker There's nothign wrong with the Bachmann mechanisms, particularly their steam locos. They are generally good and smooth runners. Removing the capacitors will help even the Bachmann DCC decoder - but it really IS that bad. No silent running, no BEMF, no support for start/mid/max or speed tables. Etc. There's a reason you can get a loco that cheap witht he decoder already installed. Look how much they actually charge for those decoders if purchased seperately. You can get a far superior decoder from NCE for a lot less than that. Their locos with sound included use Tsunami decoders - those are good. The non-sound Bachmann decoders though - just say NO. --Randy
Randy -
Thanks very much. I think that answers my question.
Despite what many people will claim:
A good working locomotive WILL work better on DCC than DC. The reason being is a GOOD DCC decoder can monitor the motor and determine if & how it is rotating and adjust the voltage pulse accordingly. (It's often called BEMF) This will allow continous slow speed operation.
Unfortunately the Bachmann DCC decoders are borderline at-best.
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
DigitalGriffin Despite what many people will claim: A good working locomotive WILL work better on DCC than DC. The reason being is a GOOD DCC decoder can monitor the motor and determine if & how it is rotating and adjust the voltage pulse accordingly. (It's often called BEMF) This will allow continous slow speed operation. Unfortunately the Bachmann DCC decoders are borderline at-best.
Somewhat misleading. Anything that can be accomplished in a DCC decoder can be accomplished in a DC throttle, including BEMF. In fact, you could take a DCC decoder and throttle system, install them on/under the layout, and use them as a very expensive DC throttle.
But that is beside the point. BEMF, if used judiciously, can slightly improve slow speed performance over most pulse power schemes. After all, the TAT series of throttles going back to the TAT III in 1963 also used feedback to enhance performance. BEMF (and other types of feedback control) can also be used to mask binds and other causes of jerky mechanical operation. And BEMF can be used as a "cruise control" to set a particular speed, and let the train run.
My personal preference is to get the locomotive to run well on straight DC, with no binds or problems in the mechanism. Then the extra slow speed generated by pulses overcoming motor cogging is icing on the cake.
In real operations - not "how slow can you go" contests - switching is generally performed at 5 scale MPH or faster. Many folks would get bored out of their minds if they actually did all their switching at 5 MPH (takes 6 full seconds for an 8 wheel diesel switcher or 40ft box car to pass a switchstand). Almost any decent locomotive mechanism in good condition will run all day at 5 scale MPH on straight DC. PWM or other pulse systems can generally take the minimum speed down to 1-3 MPH. So for most folks, the pursuit of ultraslow operation is not the holy grail it is made out to be. The other uses of BEMF are even less realistic or desirable, so I don't see a great value in BEMF.
my thoughts, your choices
Fred W
Is the capacitor the yellow part numbered 104 in the picture below? (Thanks mfm37)
I
Yes, and there might be another on the other side connecting the other motor brush to the motor case.