More DCC woes

[mecgp7]

Following up on my earlier post about older decoders, I can add reason 637 as to why I hate DCC. Could someone explain to me how a DCC loco can go off at light speed when the throttle is at zero and the direction set at stop (Digitrax system)? Especially since the loco address has not been entered? I assume there is still power to the tracks as one can operate lights, etc. My guess is a fried decoder?

[nickelplate759]

Yes, there is always sufficient power and voltage present to enable a loco to travel at light speed.

As to why - I only have experience with one decoder behaving this way - the TCS CN (also CN-GP, which is really the same thing in a different shape).  It's a 2-part board, with three wires between them, but both boards must also make contact with each half of the loco chassis.  If the secondary board does not, you get exactly the behavior you describe.

[mecgp7]

As this is a one piece board, I assume there is little to be done to fix it. Not a huge issue for me as I don't use DCC and I have analog boards.

[signalmaintainer]

Following up on my earlier post about older decoders, I can add reason 637 as to why I hate DCC. Could someone explain to me how a DCC loco can go off at light speed when the throttle is at zero and the direction set at stop (Digitrax system)? Especially since the loco address has not been entered? I assume there is still power to the tracks as one can operate lights, etc. My guess is a fried decoder?

Just to clarify, the locomotive is on a DCC system this time, correct? Is the analog bit in CV29 disabled? If not, what you described can happen.

DCC is not that difficult to grasp at its basic user's level.

[peteski]

Yes, most likely issue is that for some reason the decoder "thinks" it is in DC mode, seeing full voltage on the track, it takes off like a banshee.

This is fairly common misbehavior, and also as mentioned the remedy is to turn off the alternate power source bit in CV29 (aka. "DC mode").  This is nothing new to anybody who has been dealing with DCC for some time.

What to set the CV29 to? I can't tell you without knowing its current value.  If you want to figure it out yourself, look for a CV29 calculator usig your favorite search engine.

And no I'm not going to lie, DCC can complicate operating model trains, but the additional functionality DCC offers greatly outweighs the additional complexity of dealing with DCC. At least in most cases.

[mecgp7]

I have no idea about CV29. I have very little knowledge of DCC, but I can follow step by step instructions in the Digitrax user manual and let's just say that they often do not work. In all fairness to DCC, the locos I am testing are generally used and in this case the decoders are older models. It just seems like there are so many more issues one can have with DCC than analog. I have locos whose address I can read, but can't get them to run. I try to re-read the address and it is different. Usually it goes to default 003. Take the loco off the track and read the address again and it matches the original assigned loco number. Either way the loco doesn't run with either address. I have ensured conductivity everywhere and have included the little resistor trick on the program track. This is a must with the system that I have. No resistor and nothing works. Perhaps it is my Digitrax system which was also used when purchased.
I admit to having limited knowledge, but if I were a newby with no knowledge then the system would have hit the trash a long time ago.

[peteski]

Like I mentioned, DCC (basically computer controlled model trains) does complicate operation when compared to DC.  Just the fact that it is programmable, makes it  more complex than DC. While DCC does simplify track wiring (compared to block-control DC), the operations and programming adds complexity. There is a learning curve involved, and it is not for everyone or for every layout.  And yes, there will also be glitches, although some if the weird behaviors you describe don't seem to make sense. At least in my DCC experience.

I also agree that if some newbie got into DCC, but was unwilling to take the time to educate themselves about DCC configuration and operation, they would quickly become frustrated.  The more knowledgeable about DCC one becomes, the less frustrating it is. DCC is far from being easy or perfect.   Some modelers prefer DC, and even go as far as removing decoders from models which came DCC equipped.

Also, in my experience Digitrax (while being the most popular in USA), IMO not the easiest or most intuitive DCC system to operate.

[mecgp7]

Good feedback. I only have the system to test DCC locos for future sale or sale of the decoder. Essentially, I don't get off of page "one" which is how to read an address, program an address and then run the loco with said address. Rarely does it go well. I have a dedicated DCC testing station with one purpose and that is for testing the most of basic commands. These are the same commands over and over again. I never even venture in to CVs or whatever. If it were a rarity you would never hear from me, but it seems to be the norm. Maybe I need to invest in newer system.
I am sitting on two such decoders that I would be happy to trade for analog boards if anyone is interested. They are from Atlas GP38s. You would be welcome to try them out first.

[MK]

I'm assuming you have a track for programming and a separate track for running/testing?

[mecgp7]

Yep. A track for both.

[signalmaintainer]

I have no idea about CV29. I have very little knowledge of DCC, but I can follow step by step instructions in the Digitrax user manual and let's just say that they often do not work.

Set CV29 to 6 to enable analog mode, set to 2 to disable analog mode.

Obviously the Digitrax instructions do work, although they are not as well written as they could be.

[mecgp7]

Out of my wheelhouse setting CVs. Wouldn't resetting the decoder to factory default do the same thing? I think I figured that out once before although I don't remember how.

[signalmaintainer]

Out of my wheelhouse setting CVs. Wouldn't resetting the decoder to factory default do the same thing? I think I figured that out once before although I don't remember how.

No, default setting is analog enabled, CV29 value of 6.

[mecgp7]

You lost me at "CV29 value of 6" . I just haven't done it before.

[peteski]

"2"? "6"? Not a good advice.  Blindly setting CV29 is not helpful.  We are assuming things.

LIRR, factory defaults will leave the DC mode enabled (so the decoder will universally run on DC or DCC).  If you don't even want to deal with modifying CV values, I get the feeling that you really don't really want mess with DCC.  I'll mention again:  there is a learning curve to use DCC. Like reading the manuals.

Also, just to put things in perspective, in the past I was in your shoes, but I really wanted to learn how to use DCC and all the exciting features.  After reading manuals, asking lots of questions, I got to the point where I understand DCC and know how to use it to my advantage.  Notice that I didn't say "I mastered it" -- just "understand".

EDIT: Digitrax documentation is usually not very easy to understand (and the procedures can be a bit awkward), but between the manual and asking questions, you should be able to get a better grasp of DCC.  Find a section in the manual on how to read/write decoder CVs using programming track. Based on my experience, for a starter set NCE Power Cab is more intuitive to operate,