Programming problems on DCC OnBoard Engines

[doodles113]

Hi,
There's my first post here in discussion boards,
and i hope finally find someone who has the answer to my question.
I have 3 Bachmann engines with DCC onboard ( GP35,SD40-2,GE 70Ton.)
and i recently have programmed the SD40-2 to run in a layout with DCC.
After this, the engine doesn't run in any layout with a DC controller, only in DCC.
Any ideas?
Thanks in advance,

Eduardo

[Hunt]

Likely during programming the Alternate Power Source, which is Bit2 of CV29, has been disabled.

You did not tell us what DCC system you are using.
If your DCC system is capable of CV READ,
  What is the current value of CV29?
  What is the current value of CV12?

If your DCC system can not read CVs, then start over and reset the value of all CVs on the decoder to their factory set value (decoder default CVs value) by programming a value of 8 to CV8.

[doodles113]

OOOPS... i didn´t put this information...
The DCC system is MRC(not sure about what exact model, i will check this with the owner), but  i´m almost sure of the ability of the DCC system to read/program the values of indicated CV´s...
I will check the current values and i will post here the results.
Thanks for help!

[PaulDeS]

Hi Doodles,

I had the same problem when I first setup my Bachmann locos with my MRC system(actually it would probably happen with any train).

If you set the loco address to 1 thru 127 then you need to reset CV 29 to 6. If you set the loco address to 128 thru 9999 reset CV 29 to 38. This will turn DC (analog) operation back on, I don't know why but the MRC system resets CV 29 to a value that turns off DC operation when you set an address.

[Hunt]

doodles113,
Yep, darn those DCC systems that do what they are designed to do! 

You probably can tell from my questions to you I thought you are using one of the MRC DCC systems. However, not all MRC DCC systems disable the Alternate Power Source.

Also, I have not taken the time to confirm the CV29 values PaulDeS gave.



PaulDeS,
Here is part of a reply I wrote you 6/8/08

What you have discovered is what some of us familiar with DCC refer to as an undocumented feature. You will discover even more strange implementations by MRC of the NMRA DCC Standards and Recommended Practices. MRC seems to just do their own thing. Sometimes the folks at MRC seem to be as surprised about some of the undocumented features that surface in MRC DCC command stations and decoders as the rest of us.

That said, I always suggest:  One of the first thing to do when using DCC is to change CV29 on any decoder to disable Power Source Conversion. This eliminates several possible unexpected anomalies. Very important to do this if running on an old club layout that was converted from DC power to DCC.

[PaulDeS]

Hello Hunt and Doodles,

Hunt, your response to me back in June is what made me go to the MRC website and find the table of values that I gave to Doodles. And I thank you for the prompting. There was also an article on the website that was helpful in finding ins and outs of the MRC DCC system.

By the way I have a Prodigy Advance Squared. It works find with all my Bachmann engines and when these quirks show up I run to this forum and the article from MRC (written by Frank Verrico of their Tech Service Dept). The article has a long title that goes like "Prodigy Advance, Advance squared, Wireless Conversion and Express Tips and Tricks"

Hopefully the information will help Doodles over his problem.

[yguy]

I am using MRC express and want to deprogram the DCC and run my Bachmann engine on DC .
What code do I enter in my MRC cab running my engine to switch from DCC to DC.
I plan to use a three way toggle switch to alternate from DC to DCC in my rail yard.

[Joe Satnik]

Dear yguy,

Remember that your engine's front wheels are wired (shorted to) the back wheels.   

Don't ever run across the gap between your main (DCC) and your yard (while DC).   

If you do, chances are good that you'll get to sample the smell of a burning DCC decoder, DCC command center or DC power pack. 

The only way I would allow such a scheme would be to have some kind of automatically activated physical barrier that would block passage between the two areas whenever the yard was DC.

Hope this helps.

Sincerely,

Joe Satnik