Decoder goes dead for no reason

[OldEastRR]

I just don't get DCC. It's very complex and inconsistent. I'm still not convinced you don't need deep electronics experience to actually make it work. I hardwired a decoder into a loco, it ran fine. there were glitches once in a while when it forgot its address number but for the most part it ran. Left it sitting on a non-powered layout for a week, tried it ... dead. A friend took it to a club where they had sophisticated equipment told me the decoder wasn't dead, it wasn't sending power to the motor. Registered the decoder on the programming track, could turn the lights on and off. Took the thing apart, tested all the wires running from the decoder to the various assemblies, current flow through all. Tried reset. Dead.
I'll try to get Digitrax to take it back AGAIN (first time the wires came off while I was trying to install it). But I wonder what the fk you have to do to get decent DCC. Any static electricity, any derailing, any dirty piece of track can send a loco flying or dying. I just don't get it. I've got no reversing loops, all frogs isolated, lots of feeders, a Zephyr pack ---I haven't tried any but a couple of CV changes to decoders. I guess some people are lucky with DCC, some aren't. Very very complex science. It's not just push a few buttons, add all kinds of neat features to your loco. Nope.

[peteski]

Ah, another rant.

Curious that from all the scores of people running DCC, you seem to have very bad luck with those pesky complicated new-fangled DCC thingies.
There is no magic or rubber chickens to spin over your head, or live-animal sacrifices. All you have to do is make sure your motor leads are reliably isolated from any other electrically-live part of the model.

[Mark W]

All you have to do is make sure your motor leads are reliably isolated from any other electrically-live part of the model.

Just gonna reiterate this and add; if the locomotive itself is a poor runner on DC, it's gonna be a poor runner on DCC.  These are miniature mechanical toys.  Quality matters!

[robert3985]

I remember the very first decoder installs I did were at a show on three Kato E9's.  Used "drop-in" Digitrax non-sound decoders and it took me about 8 minutes apiece following the Digitrax instructions.  I had a crowd of onlookers watching me do it.  Took 'em over to the program track and gave them new addresses, consisted them and ran 'em for three days at the show.

When I got 'em home, I took the shells off and soldered the two contacts on either side of the decoder to the pads rather than rely on Katos little tab-lock thingy to keep proper pressure on the stock Kato tabs, but I'd had no problems with 'em at all.

The only other problem I had was with MRC sound decoders in my Athearn Challengers.  Needed to get a Soundtraxx PTB-100 programming track booster, which I did, and all of a sudden, I could both read and program my MRC sound decoders.

I don't have an electronics degree and I have to refer to my chart to read resistor values, but I have never had a "bad" decoder, or ever returned one, or ever had one go crazy from static discharge.

Contrary to what Peteski thinks, I think the OP just has bad DCC mojo, and should get a witch-doctor to kill a chicken or two and get rid of it... 

Cheerio!
Bob Gilmore

[Greg Elmassian]

Coming late to the party, am I guessing right we are talking N scale?

Greg

[peteski]

Coming late to the party, am I guessing right we are talking N scale?

Greg

Yes, the Railwire is mainly an N-Scale forum. But not mandatory. 

[John]

Ah, another rant.

Curious that from all the scores of people running DCC, you seem to have very bad luck with those pesky complicated new-fangled DCC thingies.
There is no magic or rubber chickens to spin over your head, or live-animal sacrifices. All you have to do is make sure your motor leads are reliably isolated from any other electrically-live part of the model.

Be nice Pete . .. electronics and technology are not second nature to everyone ..

[peteski]

Be nice Pete . .. electronics and technology are not second nature to everyone ..

That was my "nice".  It was not just about a level of electronic knowledge - it was about the attitude.  We are trying our best (in multiple threads) to help Al with his problem.

[Greg Elmassian]

Unfortunately it is easy for frustration to turn to anger.

From my "newbie" point of view, there are multiple threads, and in every one someone is trying to help.

I'll apologize in advance if I am pouring gasoline on the flames. 

Clearly people "helping" need to be cognizant  of the level frustration the person needing helps has.

On the flip side: people asking for help need to also work with the people trying to help. I cannot enumerate the times that I've tried to help someone, and they get upset, or refuse to try what is suggested, often replying that the suggestion could not be the problem.

I have had to say: "look, you are asking me for help because you cannot solve the problem yourself, and then you argue with me on my advice to solve the problem", and then the line in the sand is drawn, they can listen or stop asking, but arguing is out...

So, let's be sensitive to both sides....


Greg

[CNR5529]

I have had to say: "look, you are asking me for help because you cannot solve the problem yourself, and then you argue with me on my advice to solve the problem"

Not that this will help at all with the situation at hand, but apparently there is a word for that! Implausintransigence 

http://mrsvc.blogspot.ca/2017/01/implausintransigence.html

[Greg Elmassian]

Love it!

Notice he uses the term "SMH", look up the author of "SMFH" in the urban dictionary...   

Greg

[tehachapifan]

My experience so far with DCC has been quite positive, however there have been some strange occurrences that have happened here and there. Some I've figured out (often with help here) and some I haven't. Some issues have been downright frustrating as heck! While I am of the thought that decoders and DCC systems are generally well-built and surprisingly hardy, they are still pretty complex gadgets and things can go a bit wonky at times....enough for me to kind of pause and hold my breath every time I power things up (not that anything bad has happened on power-up yet). For an added buffer against the DCC gremlins, maybe I need to add-in the magic chicken ritual mentioned earlier.

[peteski]

DCC systems are generally well-built and surprisingly hardy, they are still pretty complex gadgets and things can go a bit wonky at times.

Yes, if one thinks about it, every decoder is a complete computer in a very small package.  A non-sound decoder has a processor, Flash memory, which holds its operating systems (firmware) and the CV registers, random access memory (for storing real-time operational data), and several input/output devices (voltage sensors, drivers for the motor and functions, etc.). It also includes several timers.  Sound decoders are magnitudes more complex that that (as they also include a sound processor, large Flash memory to store the sound files, and also an audio amplifier. There are literally millions of microscopic transistors inside all those chips on a decoder.

DCC decoders are fairly advanced pieces of computer equipment - much more powerful and capable than my first home computer (Sinclair ZX81).  As we come to expect from any computer, things can go wrong for many reasons. But generally speaking DCC decoders are quite robust and reliable.

[OldEastRR]

I may be getting close to an answer about the RDC, anyway. What happens when, on a DCC-equipped loco, a contact from the motor touches a pick-up strip?
Had thing on the club layout again, it ran fine for a while, then did the running off full speed, stopped it, then ran nice, then fullspeed, stopped it etc etc. -- my friend disabled the DC option so that's not the answer.
The LED board burn-up apparently comes from current all running through only one LED instead of one both lit at each end of the RDC. That was a hassle changing and resoldering wires so a different LED lit up at each end at the same time. Then I had to replace the resistor. Still haven't got that to work....how the fk are you supposed to solder on these tiny SMDs and itty-bitty wires in very crowded boards? Is there some soldering iron with a tip the size of a #53 drill bit?
What's really discouraging about all this DCC mess is the many hours I'm spending trying to get locos to work right. Time I could be spending on scenery, buildings, rolling stock work, or just plain running trains instead used up on DCC mess. I build the first super-sturdy, perfect trackwork layout in my life and can only run a couple of locos on it. Model railroading is f -... well, fun is not the word I was thinking of.

[mmyers]

When a motor contact touches a rail pickup as you describe, the train runs away at full power because it is now getting full voltage from the track. It also burns the motor output of the decoder rendering it useless. this is why isolation of the motor brushes (and the orange and gray decoder wires) is so important. Unfortunately there has never been a practical way to protect the decoder's outputs when this happens. 
Same outcome can be expected if one or more of the function wires makes contact with a rail pick up. Minimum, that function is destroyed. Maximum, whole decoder is fried.

Martin Myers