# Decoder robustness



## ggnlars (Aug 6, 2013)

My research has discussed the various loco performance differences between various decoder models and manufacturers. No where have I found any discussion about the fundamental robustness of decoder a vs b etc. It would be interesting to hear what others have experienced. 

The topics That would be interesting are:

How many of a given model had some flaw right out of the package? Is this a quality control issue on the manufacturers part or the users?

How long do they last in normal use, i.e.- running trains in a normal mode

Are some more susceptible to damage due to shorts in the track, or the converse are there decoders that handle this situation better than others?

Are some decoders more susceptible to "runaway" than others?

I know there are several other points to consider. Feel free to bring them up. This is not meant to pick on one manufacture or another, the intent is to try to see if there are any trends that are significant and are there any solid winners. Are we wanting more out of the decoder than the current circuit can handle. For this discussion do no include sound decoders. They are a problem unto themselves and possibly would require a new set of criteria.

Any input?

Larry Dunbar


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## Brakeman Jake (Mar 8, 2009)

In many cases,it's a matter of installation...all decoders that I know of can be fried in no time if poorly installed.There are some precautions that needed taken like is motor properly isolated,it's power draw,etc.If installed properly,most will last quite a while.

Then you have preferences.Some will offer more features,or will control the speeds more smoothly than others or will program easier or else,other reasons particular to every modeler.

Obviously,there's a failure rate like in everything else.A component can fail for no obvious reason,whatever brand involved.That's why there are warranties for these cases.

Then if you want names,I've had good results with TCS,NCE and Digitrax...never had a failure with them yet.Can't comment other brands....


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## ggnlars (Aug 6, 2013)

*Yes this is a start.*

This is the kind of thing I'm looking for. 
My experience is different from yours. I have checked out 8 decoders in the last week with my ESU decoder checker and My NCE Power Pro DCC system. 2 were TCS and like you the TCS check out fine. The NCE were a different story. The 6 NCE decoders I worked with were the 2 D13SR's that came with the Power Pro set. These were ok. The DA-SR's were part of a 4 pack, 2 were bad. one of these started smoking while being tested. The aligator clips were securly clipped to the proper place and not touching any other metal on the decoder or each other. After the smoke cleared, it would run in one direction but not the other.

I am very good with electronics. These decoders were faulty. I will take care of getting my money back. 

I found some other issues with the NCE decoders. I installed one of the TCS units in an Atlas ROCO loco. again it ran fine in both DC and DCC mode. I realize that most people will only want to use DCC, but it seems to me that one of the attributes for the decoders is to be able to run on DC if one chooses. Again the TCS ran great both ways. 

I have installed one of the DA-SR's that worked and one of the D13SR's in two diffferent engines. Both worked fine in DCC mode and both were similarly very erratic in DC mode. They both would stutter start and then if I turned the power off and changed the direction on the MRC DC transformer, the unit started again, but did not change direction. Again both worked fine in DCC mode. Reversed direction with the push of the button on the Power Pro and the LED's lit in the proper direction. As I said they worked fine. These were installed in a P2K SD9 for the DA-SR and a Atlas ROCO GP40 for the D13SR. 

Based on the criteria of quality control and ability to run on DC, which is a NMRA requirement, the TCS decoders in a sample of 2 worked fine, the NCE in a sample of 6 did not. This is by no means a statistical significant result, but it started me looking and thinking about the overall decoder robustness. 

What I would like to find out with this thread is what issues and satifaction levels exist within the community. 

I'm am looking to add decoders to my expected fleet of loco's, over the next few months or years. I would like to know that the decoder type or types I selected were the smart choice at the time. Yes, the individual decoder and installation will impact that, but are there decoder designs that are better than others. And against what criteria. The only way we will bring that to light is through the exchange of experiences. 

Lets hear some more discussion.

Larry Dunbar


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## DonR (Oct 18, 2012)

Somewhat surprised at what you have reported about the NCE decoders.
Those and Digitrax seem to be the most highly praised here on the Forum.

I couldn't comment...I have only factory installed...gasp...Bachmann DCC
decoders.  I have had no problems with 7 of them.
But others on the Forum don't regard them highly. They also lack
many features standard on other makes.

It will be interesting at what others say about their decoder experiences.

Don


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## Hutch (Dec 19, 2012)

I can tell you the only negative experience I've had is with Digitraxx SDH164D sound decoder. I t works great as long as I program it on the programming track. If I try to program it or any other decoder while it's sitting on the track, I need to restart my system. So I have to remove that loco if I'm programming others on the main. This is all with the MERG system that I like very much and works great with all other decoders that I've tried including Tsunami and NCE. I haven't tried a non-sound Digitraxx to see if I get the same results.


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## musicwerks (Jan 4, 2012)

I am pretty new to DCC..

Hornby decoders- horrible. They can run at slow speeds for my proto engines when I tested it. 

When I installed onto my vintage tender driven Flying Scotsman (following Hornby website manuals), it ran well for a day. It smoked the next day when I ran again. It seems not being able to supply enough Amps to the crappy older hornby motors. The wires also came off later ( 'whiskers' falling off decoder...bad). Now I have reconverted my Scotmans back to DC, it cant run properly..stutters. It used to ran really well in DC, abit the bad smell.


I will NEVER buy Hornby decoders ever in my life (cost me approx USD39).

So far, Digitrax DH123 and Bach-DSL seemed to work well for me when hard-wiring older Bachmann and Mehano GG-1s


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## Brakeman Jake (Mar 8, 2009)

Older locos generally have higher current draws and yes the decoders do have a limit to what they can supply wich is clearly stated with the decoder's instructions.If you didn't check the current draw of the loco before installation and indeed overloaded the decoder,no wonder it eventually smoked.Don't blame the decoder,you somehow asked for it.

Most very old locos do need remotoring before they become candidates for DCC.


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## ggnlars (Aug 6, 2013)

What I think your saying is that the decoder does not have any margin built in above what is listed in the paper work. There are a lot of reasons a motor might draw high levels of current. In the normal mode these motors are not well maintained and will eventually be a problem. Yes the new motors are designed to operate at a lower current level when new, but they have to live in the same hostile environment as the older motors. Dust, miost conditions, etc. It seems that is a decoder robustness issue. 

musicwerks pointed out that his experience with Digitrax DH123 and a Bachmann on other old motors is not the same as he had with the Hornby. Is it because the design spec that they used is less on performance and more on reliability?

Larry


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## ggnlars (Aug 6, 2013)

I have some additional experience that I just thought of. I have collected 11 other loco's over the last few years that all have some DCC decoder in them. Three are MTH, these also have sound. Of these three, all of them worked great on DCC. Two worked fine on DC. The other one did not work on DC at all. I recently reset the settings, but it still did not work on DC. 
The other eight are Athearn Genesis F units. Four have sound. These were acquired a few years ago, before I had a DCC system. I checked them out on my DC system and they all worked with out a flaw in the bunch. Based on what I have read on other threads, these Athearn units are MRC decoders. 

All of these were only test run to be sure they worked on receipt. All eleven were factory installed. It is a limited usage sample, but it does add data to the list.

Larry


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## Brakeman Jake (Mar 8, 2009)

There are two probable reasons (beside a faulty decoder) one of your MTH locos doesn't run on DC.First it may have an older generation decoder aboard that doesn't accept DC or it may be that it is a newer one with the DC feature de-activated.

As far as MRC sound decoders are concerned....I wish you the best of luck with them.In my opinion,for what it's worthed,they have no flaws...they are flaws.They have a stunning failure rate.I had three of these...two failed...and the third one was about to,it had started melting the plastic shell on top of it.They've since been replaced with Tsunamis.


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## ggnlars (Aug 6, 2013)

I'm sorry I brought sound into this discussion, because I think sound brings a whole set of baggage that would require a new set of criteria. I would ask how long did they last? If I remember right on the units I have you can turn the sound off. Did you think the decoder running with the sound off would be more robust or do they just have a short life span?


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## Brakeman Jake (Mar 8, 2009)

I wasn't modeling when the first silent decoders showed up some twenty or more years ago but I have a feeling that the first ones were pretty basic with likely a higher failure rate.From then on,they have constantly improved their designs and offered a larger choice of features so that right now I'm convinced that silent decoders from reputable manufacturers are very reliable,provided they're installed as they should be.

Then a few years ago,sound decoders entered the scene and are now going through the same evolution.Quality is improving and the number of features offered are multiplying at an amazing rate,to a point that DCC systems manufacturers have to develop more and more functions into their controllers to keep in the game.Now,you can have twenty-eight functions controllers and I'd bet that a few years from now forty may be the norm.

But there's a limit to this and it's the cost of development.The technology is there no doubt but there has to be someone to buy it so the whole thing is a juggling act.Developing increasingly better decoders while maintaining the prices at an affordable level borders the impossible.

I understand the modeler who is walking a tight rope with his modeling budget and always attempts to keep the costs down.However,in my opinion,decoder choice shouldn't be part of this.Good reliable brands cost more to develop thus cost more to the buyer and there's no way around this.

MRC keeps in business playing the other end...they're cutting short on development,thus costs,to appeal to the less econmically capable modelers.If only they offered fewer features and programmable options,wich they do,I'd say that goes with the price and the buyer accepts this.But with their high failure rate is unacceptable and they seem to get away with it still.

To your question...well I don't know.I suspect turning the sound off would help some...a electronician probably can tell.Are the sound processors still active when muted?A good question indeed.Then I think your MRC decoders are HO units,so likely bigger and tougher than the ones I had (in theory),mine were N units (Athearn steamers) and the better one lasted about three hours total.I had to use it minutes at a time,allowing it to cool every now and then.


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