DCC question/problem

[Anonymous]

Last week a couple of members of my train club bought a Prodigy DCC system and a Train with a MRC decoder in it to use. They asked me to hook it up and show them how it worked because I had been doing some reading on DCC. Well between taking care of derailed trains by my kids and hooking up the DCC I finally got it working. I had the DCC train running with a non DCC train and demonstrated how you could have different speeds/ turn on and off the lights and so on , everyone was happy. Well this week I come in to the club and immediately on arrival people came to me with a few problems. The non -DCC trains were running extremely slow on the track with the DCC box at full throttle, I went over and checked it out and it definitely seems the case. Also when you brought an engine to a stop it would just sit there and hum with its light on even though the throttle was zero, the only way to make it stop was to shut off the DCC. Anyone come across this or know a solution? Unfortunately I didnt have a choice of the DCC so I'm pretty much have to work with what was given to me. Thanks for your help in advance.

Orion

[Anonymous]

I would also like to see to see a fix and or a explanation of the problem, As I have been looking at this system as a possible purchase.
Andrew Miller

[johncolley]

I have heard, but not documented, so take it as one thing to look at, that running a DC motor on DCC will gradually eat up the commutator because DCC is really a lot of spikes of a higher than normal voltage. Unless it was sitting idle while the DCC train was using high throttle, I don't see how it could have done it that quickly. Better to check with some folks who know, such as Bruce Petrarca at Litchfield Station or Mike at Max trains. Please post your findings to share, thanks.

[skir4d]

Well, even with the throttle in the off position some DC motors still buzz with DCC on the rails as the DCC signal is constantly fluctuating.

As far as running slower at full throttle than they did before is it possible on the Prodigy to program a speed curve for the DC locos? Some one might have done that accidently. Damaging the commutator would make then run rougher than a cob at slow speeds but shouldn't affect full speed. And if you had burnt out one of the field coils it shouldn't run at all. Try one on straight DC and see if it behaves as it did before.

Jack W

[jwmurrayjr]

Hi,

I've been running DCC for about 2 years (the life-time of my layout). I occasionally run a non-decoder DC loco but not often. One of the main objections is the "buzz" that is caused by the alternating current in the track. The buzz is most noticeable when the loco is at rest or running slow. As it increases speed the noise reduces.

This noise is a given with DCC and DC loco. It's not a flaw or peculiar to any one DCC system. It's caused by the constant relatively high track voltage (usually about 15 volts) alternating an pushing the DC motor back and forth rapidly. To run a DC loco the DCC system shifts the phase when "00" is addressed and the specifics of that shift determine the speed and direction of any DC loco on the track. This "shift" does not have any effect on decoder equipped locos.

Running a DC HO loco on DCC doesn't seem to harm the motor. But you should not leave the loco on a powered track when not running as it could heat up. But the noise will probably remind you to remove it. Locos perform SO much better with DCC that the 00 address DC feature is more of a novelty and sometimes a convenience than a feature that you would want to use often.

I don't think that you can control the lights on a DC loco on a DCC system, but I'm not familiar with the Prodigy system. DCC light control (and bell, horn and other functions) is a function of the DCC decoder.

You can find a lot of good DCC info at Tony's Train Exchange, Loy's Toys or other sites on the web.

[Anonymous]

Jim is correct - what you are seeing is typical of a DC loco on a DCC track.

No one has ever PROVED (that I have seen) that the "buzz" causes any damage to the loco.

The solution - get decoders !!!

Or go back to DC until more of the club members have converted their locos.

[newhavenguy]

I think you've got DC and DCC blocks on together causing the slow down. If your going to run DCC on a DC layout, make sure all the blocks are lined for the DCC cab that you are using. And all the DC blocks to the DC cabs. Think of it as the DCC controller becoming one cab and the others regular DC. If you flip the switches to more then one DC cab your trains will slow down and you lose control and speed. You have both AC and DC on that block.

DCC is actually AC current to your track. Hence the buzzing on non decoder equipped locos. The decoders for DCC take that AC current and turn it into DC for the motor, lights ect. AC is used as a carrier as it is less susseptible to noise then DC. You need that when the command station is sending out commands to the decders all over your layout.

I think if you only run the DCC equipped loco with the blocks set for the DCC cab and DC blocks set for the rest half your slowing problems will go away.

When you guys figure out that you can run more than one DCC decoder equipped loco on the same track at different speeds in different directions and NOT have to throw block switches anymore, you'll come to the realization that DCC ain't all that bad. You'll run your traind not the layout block switches.

I use NCE. I changed my mind the first time I saw DCC in action. I'm glad I did.

[cacole]

There are some serious limitations to the Prodigy system unless you have the newer release. The buzzing of a DC motor when you try to operate it on DCC, as others have mentioned, is caused by the fact that the DCC system is having to take a DCC pulse and lengthen it enough for the DC motor to respond; positive for forward and negative for reverse. This is hard on a DC motor because it is continually being pulsed by a high voltage of between 14 and 15 volts. This rapid pulsing generates heat in the motor and can shorten its life.

A Prodigy is not suitable for a club layout because it does not have sufficient amperage output to run more than two or three locomotives.

[Anonymous]

It can be used for a club. I've seen it done. You just have to hook up the power booster pack mrc puts out. Though you couldn't use it if your club had more than 32 engines. Plus the cost of adding inputs around the layout is also expensive. I find this system would be good for a midsize layout 20x20 with about 20 locos. It's a fair priced system. A system I could by with 2 extra handhelds and not go bankrupt. Seeing I can only spend about 100 a month on MRR.
Andrew Miller

[AntonioFP45]

0ri0n,

Great info from the above posts.

Just my two cents. I put my Atlas DC locos on a DCC track which of course resulted in the noise, though the locos ran smoothly. According to a close friend who is a computer electronics expert when the DC locos are making the noise; electronics techs will say that the DC motor is "SINGING" (strangely enough). The above descriptions with what is happening to the motor are accurate.

This goes for any electric motor experiencing similar characteristics, not just model locomotives.

0ri0n,
DCC decoders have gotten pretty cheap. TCS has basic ones for $14-$24. Go for it!

[Anonymous]

Thanks everyone, I appreciate the help. There is a lot of great information here. After reading this I can make a pretty good assumption on a few things after I read your posts. I checked with the club and the DC trains ran at the correct speed on a DC track. Our layout is definitely to big to run the system the members bought without a booster pack. And that at the moment the only DCC train we have in the club is the one they bought at the same time they bought the DCC controller. At the meeting they officially/unofficially put me in charge of the DCC system becuase of what I have read here and on this forum. LoL. And one of the items they appointed to me was to find out the cost of the decoders and how to install them. Again thanks for the help. I look forward to learning more.

Best Regards,

Orion

[Anonymous]

Another thing to think about is if you want install the decoders yourself. Since it is a club you probably have all types of different brands and styles of engines. So it might be hard to how to put in a decoder on each engine. If you good with electronics then it might not be a problem but if your anything like me this may not be as easy. There are a couple places that will do this for you for a price. Depending on the store it can be as little as 5 dollars. In my LHS they do a 5 dollar charge for the first engine and multiple units he sets a fair price for.

Words of advice if you plan to let a shop install a decoder. Make a receipt youself of the brand of engine, roadname and model. Have the store owner give you a receipt also. Keep both of these in a safe place. If you have a digital camera a photo of your loco probably wouldn't hurt.

When you go to pick it up ask if they can test it for you before you leave the shop. This way there is no dispute over the craftsmanship, Decoders can be burnt out while installing them. Check for damage and you should be good to go. If you send it in the mail to someone to do it ask them to check it before they send it back.

I know this may seem excessive but an engine is a big investment and your trusting someone else with it. It's just a safe gaurd so you don't get taken or get a broken engine. Even if it's a trusted hobby shop and you personally know the owner it's still a good idea to do this, mistakes happen and it's better to catch it in the store before you leave then it is to have to go back and figure it out.
Andrew Miller

[newhavenguy]

One thing I would suggest is read a few books on DCC. "The Big Book of DCC" and the new one from Kalmbach books are a good start. although "The Big Book" is slanted towards Digitrax who published the book there is a lot of good general information in there.

Forums like this are good to get started but the "meat" of DCC is in those books. There are a few more books out there too. Have a look around. The NMRA has standards for DCC and is another good source.

[nslakediv]

OriOn, try this site, lots of good stuff http://www.wiringfordcc.com/. I would suggest you and your group put your heads together and install decoders yourselves for the simple fact that if a problem exists you dont have to send it half way across the country to repair it. I am by far no electonic genius and have done over 40 locos for myself and at least 75 for others. Its very simple. Give it a try.
Randy

[cacole]

Also check the questions and answers for DCC beginners on Tony's Train Exchange at http://www.tonystrains.com

[Anonymous]

Limit the time a non decoder equiped loco sits at idle on a DCC system. You may not burn up the engine but you will add carbon to the brushes and commentator. Most of the new decoders can be programed back and forth between analog and DCC, so that another way to go. Installing decoders is quite easy unless you are color blind, I've done over a hundred and and after the first 3 its easy. The biggest problem is space and engine isolation. Also check the voltage of your headlight. The TCS decoders are inexpensive, have a programing reset and a 1 year goof proof warrenty. They also come with a programing reference sheet that is great for beginners. It even includes resister values for the various voltage lights.

[Anonymous]

Among DCC enthusiasts, it is a well known industry lie that you can run DC engines on a DCC layout. As you have discovered, the hum - which can vary from engine to engine - can be objectionable and at worse, worrisome. I wouldn't hesitate to run a DC engine on a DCC layout over a short term, lets say 6 months, but over the long term, I wouldn't want to do it.

[skir4d]

I always run non decoder loco's on my DCC layout to check them prior to installing the decoders. However, I do not like the noise... I've spent a good part of my professional life around motors and when they make noises like that it usually isn't good for them in the long term. It makes me think that the smoke is going to come out of them, and motors, like all electrical devices only run as long as the smoke is inside them :)

Jack W

[Anonymous]

I agree with with Rick. The manufacturers are sandbagging us with the DC operation on DCC claim. Technically it works but...I don't think you will be happy running DC locos on a DCC layout. Besides DCC is so cool I have never wanteds to go back to running on DC anyway. It reminds me of the situation with new computer software where they say it will run on windows 98.....

Guy

[Anonymous]

I have a Prodigy system myself. I also have
a Prodigy 8 amp booster. I run LGB engines, these are big "G" scale engines. The system works
as advertised. I can run one analog dc engine (I currently run a TWO-MOTOR engine this way) on the
tracks with decoder-equipped other locos. Yes, there is buzzing but I can turn off a block of track to spare the motors when not in use (your old block wiring does come in handy even with dcc!!).

The system is just to get me wet until I save for a Digitrax Empire Builder, but I am happy with it
because I got it cheap!!~

Note: For HO locos, you can run up to 32 engines with the addition of the Power Station booster.

And this booster ($150 street), compared with other systems, is really quite cost-effective (at least with current prices). The Prodigy now includes a switch controller handheld,too, for turnout control. You must buy the turnout decoders of course.

But realistically for a club I would go with Digitrax or NCE; they have more throttle options, and a GREAT THROTTLE matters when you buy the club dcc!!

The only prob I have is the MRC decoder AD321---its more noisy than the "DC" engine on the tracks!!!