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Various DCC Motor Control Issues

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  • Member since
    December 2001
  • From: Missouri
  • 366 posts
Various DCC Motor Control Issues
Posted by NYCentral1 on Sunday, December 6, 2009 10:54 PM

I have a few DCC issues I would like some input on.  I traded in (read sold off) my Blueline F7s and got a Blueline Mikado, and received the Mike the other day.  First off, I put a Digitrax DH165 in it for motor control, same decoder that I used on the F7s.  I set the Starting Voltage on it to 0 (default value) and the Mike does not move until about step 20.  I fiddled with the Starting Voltage value, and no matter what it is the engine doesn't want to move until I put it on 20 or so.  Any ideas about this?  I haven't really run it and broken it in yet, but this still seems odd.

Second, I have a Spectrum steam that has a Soundtraxx Tsunami in it.  I can get it to move at speed step 1, but it's not entirely smooth.  It's not until maybe speed step 3 or 4 that the movement smooths out.  This engine has been run a decent amount of time, and besides this works great. 

This is all kind of funny, because I picked up an Atlas yellow box GP7 and put a Tsunami in it, and without adjusting anything it moved on speed step 1, smooth and slow, and just runs great all the way up the spectrum. 

As you may be able to tell, I'm not real great yet with adjusting DCC motor control.  Anything I can do to help these two steam engines?

  • Member since
    October 2006
  • From: Western, MA
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Posted by richg1998 on Sunday, December 6, 2009 11:39 PM

 What brand of controller?

Is the steamer Tsunami factory installed or did you install the Tsunami in the steamer? Did you reset the decoder in the Steamer to default settings?

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
    December 2001
  • From: Missouri
  • 366 posts
Posted by NYCentral1 on Sunday, December 6, 2009 11:59 PM

On the Spectrum with the Tsunami, I installed it myself.  I'm not sure why it matters what DCC system this is because speed step 1 is the same on all of them, but it's a Prodigy Express. 

  • Member since
    July 2003
  • From: Sierra Vista, Arizona
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Posted by cacole on Monday, December 7, 2009 7:16 AM

 The difference is in the motor, the amount of gear reduction, and drive linkages.  For some models, the start voltage may need to be set as high as 30 or 40 to get a model to move on speed step 1.  This is where Decoder Pro and a computer connection come in very handy.

 Personally, I've never had very good luck with Digitrax decoders in this respect and prefer TCS or NCE.

  • Member since
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  • From: Reading, PA
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Posted by rrinker on Monday, December 7, 2009 7:34 AM

 For both steam locos - check to make sure there is no excessive binding in the side rods and anywhere int he emchanism. Steam locos have more moving arts and so are in generally more fiddly than a diesel. Neither one of those probably has a motor as good as the Atlas, either.

 For the one with the Tsunami, you might have to adjust the BEMF settings. Soundtraxx calls it Hyperdrive. If it sort of starts on speed step 1, it might need a touch more BEMF to keep it moving smoothly. Also, since this is a Bachmann - did you clip off the capacitors that are either on the circuit board or directly on the motor? These will interfere with smooth operation of any DCC decoder that uses high frequency drive, such as the Tsunami.

 For the Blueline - 20 for CV2 isn't really all that high. In Digitrax decoders, the values for start/mid/top go from 0-255, so a value of 20 is less than 10% power. Here too, adjusting the BEMF settings may help it run more reliably at the lowest speeds.

                                     --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
    December 2001
  • From: Missouri
  • 366 posts
Posted by NYCentral1 on Monday, December 7, 2009 10:31 AM

rrinker
 For the one with the Tsunami, you might have to adjust the BEMF settings. Soundtraxx calls it Hyperdrive. If it sort of starts on speed step 1, it might need a touch more BEMF to keep it moving smoothly. Also, since this is a Bachmann - did you clip off the capacitors that are either on the circuit board or directly on the motor?

 

On the Spectrum Steam I just plugged the Tsunami into the little Bachmann board where the cheap decoder used to be.  I've heard of cutting capacitors or bypassing the board completely, but hadn't tried that.  But, I also have not adjusted BEMF settings either.

On the Blueline engine, I'm saying it's not starting to move at all until I dial up to speed step 20, and I don't believe I've actually set CV2 besides whatever the default setting is. 

  • Member since
    February 2002
  • From: Reading, PA
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Posted by rrinker on Monday, December 7, 2009 6:08 PM

 The caps on the Bachmann will be parallel to the motor, so you can cut them off with no consequences. I'll bet it will run better right away. There are also usually a pair of coils, but those are in series witht he motor and would need jumper wires put in place once removed. You usually don't have to touch those, just getting rid of the capacitors is enough.

 As for the Blueline - give it some value in CV2 and you'll be able to get it to move on speed step 1. I just worked on an Athearn BB with a DH123 and it needed 45 in CV2 to start evenly with a RTR with a QSI Rev U decoder. That's after cleaning the commutator and carefully oiling and greasing all the gears and bearings.

                                 --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
    December 2001
  • From: Missouri
  • 366 posts
Posted by NYCentral1 on Tuesday, December 8, 2009 2:03 PM

Thanks everyone for your help so far.  On the Bachmann, I clipped the C2 capacitor, adjusted some settings (haven't touched the BEMF settings yet) and it is running slower and smoother.  It runs real smooth at speed step 1 backwards, but forwards you can detect the slightest hitch here and there.  Perhaps the working parts need to be lubed a bit?  It's a very hard to detect movement difference going forwards.

On the Blueline, I did have to set CV2 to 40 to get it moving.  That has it moving pretty slow at speed step 1.  It may do even better once I run it some more.  I noticed that I was wrong, and it was a cheaper DH123 I put in this engine, no BEMF.  Do you think I'll get much of a performance difference upgrading to something with that in the future?

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Tuesday, December 8, 2009 9:13 PM

 Better reverse than forward? Typical steam loco.

BEMF will usually allow better slow speed because it 'forces' the motor to keep turning at the desired speed, so those small 'hitches' in the mechanism won't stop it. The best solution is to make sure there are no such binds in the mechanism, then it will run slowly and reliably even without BEMF.

 The 'gold standard' used to be having the steam loco mechanism (with no motor/worm) able to sit on a glass plate and the wheels roll rather than slide when tilting it - get the side rods and so forth that free and it will definitely run great.

                                                --Randy

 


Modeling the Reading Railroad in the 1950's

 

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

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