Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Program a dummy with decoder but no motor

2699 views
8 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Friday, January 26, 2018 6:00 PM

 You do need a smaller resistor - the motor resistence is no where near 1K. Either remove it after programming, POM will still work, or else set a speed curve to all 0 or 1 and it won;t heat up. 100 ohm is usually good.

                            --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    October 2006
  • From: Western, MA
  • 8,571 posts
Posted by richg1998 on Friday, January 26, 2018 5:27 PM

faraway

Thanks for your suggestions.

I will go with CV 2,5 (and 6) set to zero and a 100 Ohm 1/2 Watt resistor and use decoders I have at hand. 

May be I should have mentioned that change the address and direction some times and do not want to open the shell each time.

 

That is why I used the method Bruce suggested. He has worked closely with SoundTraxx for some years and is now a regular contributor to the MRH forums for DCC.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

  • Member since
    February 2006
  • From: Germany
  • 524 posts
Posted by faraway on Friday, January 26, 2018 4:07 PM

Thanks for your suggestions.

I will go with CV 2,5 (and 6) set to zero and a 100 Ohm 1/2 Watt resistor and use decoders I have at hand. 

May be I should have mentioned that change the address and direction some times and do not want to open the shell each time.

Reinhard

  • Member since
    December 2004
  • From: Bedford, MA, USA
  • 21,481 posts
Posted by MisterBeasley on Friday, January 26, 2018 2:49 PM

You are right about needing a load across the motor leads to program a motor decoder.  But, you don't need a load to "run" the dummy engine, and it will produce the same sounds without one.

I use about an 80 ohm resistor across the motor leads, and then program the decoder.  Then, I remove the resistor and tape up the bare wires on the leads.  After a final test, I put the shell back on.

Since there's no motor anyway, things like momentum that you need to "tinker" with a bit don't matter.  You can get the sounds and the lights right before you put the shell back on.

It takes an iron man to play with a toy iron horse. 

  • Member since
    May 2004
  • 7,500 posts
Posted by 7j43k on Friday, January 26, 2018 2:23 PM

Overmod

I wonder: why not just connect up a small DC motor? 

 

The dummy already has a "disconnected motor".  Could just reconnect that one.  Electrically, not mechanically.

Then there are those who might suggest doing the mechanical connection, also.  Then what you have is a powered locomotive.  Which can be mighty useful.

 

Ed

  • Member since
    September 2003
  • 21,669 posts
Posted by Overmod on Friday, January 26, 2018 11:35 AM

I wonder: why not just connect up a small DC motor?  It's not as if you'd be sending actual CVs to the dummy for motor rotation; you just need appropriate electrical 'feedback' for built-in self test or whatever.  Make up some kind of viscous 'brake' for the shaft if for some reason the thing has to dissipate a current by rotating -- or make a motor-generator with reduced voltage or special diode or varistor output protection, if a glutton for technical overkill.

  • Member since
    October 2006
  • From: Western, MA
  • 8,571 posts
Posted by richg1998 on Friday, January 26, 2018 11:27 AM

I did that at least ten years ago.

I had a 0-6-0T with a Digitrax DZ125 decoder in the loco. I did not want to mess with the loco.

I hooked up a tender to the loco with a Tsunami Micro and speaker. Put a 100 ohm, 1/2 watt resistor across the orange and grey deocder leads. Changed settings in the decoder so as to not overheat the resistor.

This guy below says how you do that. Scroll down quite a ways.

http://mrdccu.com/curriculum/soundtraxx/tsunami.html

A non sound decoder is probably a better way to go.

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

  • Member since
    May 2004
  • 7,500 posts
Posted by 7j43k on Friday, January 26, 2018 9:50 AM

Soundtraxx makes lighting decoders:

810136 and 810137.  You won't need the built-in lights (which you can just turn off), but they offer three other outputs you can use.

You clearly don't need a motor with these.  They look like they could easily do what you need done.  Also, being the same manufacturer "never" hurts.

 

Ed

  • Member since
    February 2006
  • From: Germany
  • 524 posts
Program a dummy with decoder but no motor
Posted by faraway on Friday, January 26, 2018 9:32 AM

I like to run sometimes two engines in a consist on my small layout. One engine is unchanged and got usually Tsunami 2 decoder. The dummy has a disconnected motor (wire and drive shaft) and an older Tsunami 1 to handle ditch lights etc.

Initial programming of the dummy happens usually with the motor wires still connected. Without the motor connection fails programming (except on the main). A 1k Ohm resistor is not suficient. A smaller resistor would be a nasty "heating" under the shell.

Is there another intelligent way to let a dummy with a disconnected motor respond to programming?

Reinhard

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

There are no community member online

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!