N Scale Runaway

[peteski]

I can read and program to other locos on the programming track but there is no throttle control while on the programming track for lights, sound or motor. I've tested this to be sure this morning and all seems normal with other locos.

That is exactly how the programming (aka. Service Mode programming) trak is supposed to function. Programming only- no running.

I suspect that the person asking that question assumed you would try the lights, sound, and function control on the main line while the model was running (not on programming track).

[Maletrain]

Peteski, I did mean to test the Digitrax command station to see if it does allow for some throttle controls on the programming track, because I have seen posts elsewhere claiming that some Digitrax command stations do provide sufficient current to do so.  Not clear to me when or under what conditions that is said to occur.  I have not personally found a case where I can see it.

Anyway, James has provided the answer with respect to his situation. 

Sometimes, these inexplicable happenings are the result of more than one failure/malfunction - so I tend to test my assumptions about what components can and can't be doing.

At this point, I agree that the decoder is either fried or has some sort of very specific short circuit between some of its components, perhaps due to inadequate use of insulating tape by the person who installed the decoder.

[peteski]

In my experience with several brands of DCC systems, if a command station has a separate dedicated programming track output, that is driven by a small "programming booster" and it is exclusively used for the Service Mode programming.

Exceptions are systems which share the programming track functionality and main line functionality over the same pair of outputs.  NCE Power Cab is such system. Then there are standalone (sounds and firmware) downloaders like ESU LokProgrammer, ZIMO KLUG, or QSI Quantum Programmers which a single track output which can be utilized to uploading firmware or sound projects to the decoder, reading/writing CVs, also include a simple throttle functionality for testing the model.

I think that the more recent Digitrax sound decoders are also capable of being programmed by Digitrax's device similar to the ones I mentioned above.

[justjames]

OK, here's the latest update. My experience with decoders has been limited to drop-in units on Kato locomotives. I mistakenly identified the decoder in my first post as a DCC Concepts. I did this by reading CV's 7 and 8. Today I decided I had nothing to lose so I completely disassembled the loco and inspected it for any shorts, bare wires, loose joints, etc.  It turns out the decoder is labeled as a Digitrax DZ123. I don't know if that changes anything since the problem still exists but I felt my mistake needed to be corrected.

[peteski]

Thanks for the follow up. No James, the brand of a decoder makes no difference, but if CV8 was giving incorrect value on a read (36 instead of 129 for Digitrax), that might have been first sign that something was wrong with the decoder.  CV8 is the manufacturer and CV7 is just a manufacturer's own decoder version.