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DCC Motive Power jerky but Sound Works

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  • Member since
    February 2006
  • From: Central Texas
  • 37 posts
DCC Motive Power jerky but Sound Works
Posted by mcleveland on Tuesday, January 1, 2013 9:49 PM

I have a Proto2000 2-8-8-2 unit that was outfitted with a SoundTrax decoder for power and sound.  Unit has worked perfectly since I bought it two years ago.

The unit has had very little run time.  Now the unit is jerky when throttle is moved from positon 1 through 5.  I'm using a Digitrax Zepyhr unit.  Sound works fine.  One odd thing though, when the throttle lever is move back and forth from 0 to 5 in a slow motion the loco does move but not when left in a specific throttle p putosition.

I did put the standard DC chip set in to verify the decoder is not bad.  The unit powers up but will not move.

 

Hoping someone can provide some insight.

 

Mike Cleveland
  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Tuesday, January 1, 2013 11:06 PM

 First thing to try is do an OpSw 39 reset on the Zephyr, it's acting like maybe you accidently set that address to use something other than 128 speed steps.

 Next try resetting the decoder, set CV8=8, try this in Ops Mode, then tip the loco off the track and back on. It should now work on address 3. Then program back the desired address.

           --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
    February 2006
  • From: Central Texas
  • 37 posts
Posted by mcleveland on Wednesday, January 2, 2013 12:51 PM

Randy I appreciate the info.  Unfortunatley it did not correct the problem.  I do need to clarify one thing.  It is a QSI decoder and not a SoundTrax.  I also looked in the Zephr handbook and teh OPSW code they make reference to is 36 rather than 39.  I tried 39 as well with no luck.

Would you have any other ideas?

 

Thanks again

 

Mike Cleveland
  • Member since
    July 2003
  • From: Metro East St. Louis
  • 5,743 posts
Posted by simon1966 on Wednesday, January 2, 2013 1:04 PM

Is the issue specific to this loco?  Or do others exhibit the issue?

If it is loco specific look for mechanism binding or something mechanical.

Simon Modelling CB&Q and Wabash See my slowly evolving layout on my picturetrail site http://www.picturetrail.com/simontrains and our videos at http://www.youtube.com/user/MrCrispybake?feature=mhum

  • Member since
    February 2006
  • From: Central Texas
  • 37 posts
Posted by mcleveland on Wednesday, January 2, 2013 2:01 PM

Yes it is specific to this loco only.  I will give it a real close look for something mechanically binding it.  I don't think there is, but it may be internal.  If it is internal wouldn't I see the voltage drop significantly as the motor amps would increase in trying to turn the motor?

 

Thanks

Mike Cleveland
  • Member since
    April 2004
  • From: Ontario Canada
  • 3,574 posts
Posted by Mark R. on Wednesday, January 2, 2013 3:09 PM

If so equipped, turn off BEMF in the decoder. I've installed a few decoders in steam engines that displayed some severe jerking at lower speed steps, but went away as the engine ran faster. Turning off BEMF cured the jerking, but then slow speed control wasn't as good.

Once I determined the BEMF WAS the culprit, I was able to turn the BEMF back on and set the parameters of the BEMF to almost their lowest settings, which still gave me good slow speed control, yet still eliminated the jerking at slow speeds.

 

Mark. 

¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ

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Posted by ba&prr on Wednesday, January 2, 2013 5:22 PM

Do you have a walk around thottle (UT4X,DT400X,DT402X) attached to the Zypher ? If so youu may have the loco address on the other throttle. This can cause a conflict between the throttle and command station.  Joe

  • Member since
    February 2006
  • From: Central Texas
  • 37 posts
Posted by mcleveland on Wednesday, January 2, 2013 8:29 PM

I think I have discovered that the decoder must be bad.  I plugged a dummpy plug into the socket and set the Zephyr to address 00 and the loco runs fine.  Once the decoder is plugged back in the jerkyness comes back.  I'm assuming that some component on the decoder board has gone bad.

Thanks

Mike Cleveland
  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Wednesday, January 2, 2013 8:36 PM

 Try a decoder reset first though. The process for a QSI is a little more complicated: http://www.tonystrains.com/technews/dec_rescue.htm

Could just be a decoder setting that got changed.

          --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
    February 2006
  • From: Central Texas
  • 37 posts
Posted by mcleveland on Sunday, January 13, 2013 3:55 PM

Randy, just now getting back to you.  I spoke with QSI directly and they recommended shorting the pink and black/white reset wires for a hard reset. 

This did  the trick.  The unit reset back to address 03 and runs perfectly. 

Thanks for the help.

Mike

 

Mike Cleveland
  • Member since
    July 2006
  • 3,312 posts
Posted by locoi1sa on Sunday, January 13, 2013 7:07 PM

Your original post said it was a Soundtrax decoder?  Where did the QSI decoder come from?

         Pete

 I pray every day I break even, Cause I can really use the money!

 I started with nothing and still have most of it left!

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Posted by PennCentral99 on Sunday, January 13, 2013 10:16 PM

locoi1sa

Your original post said it was a Soundtrax decoder?  Where did the QSI decoder come from?

         Pete

Third post corrects the first post.......

mcleveland

Randy I appreciate the info.  Unfortunatley it did not correct the problem.  I do need to clarify one thing.  It is a QSI decoder and not a SoundTrax.  I also looked in the Zephr handbook and teh OPSW code they make reference to is 36 rather than 39.  I tried 39 as well with no luck.

Would you have any other ideas?

Thanks again

 

Inspired by Addiction

See more on my YouTube Channel

  • Member since
    November 2003
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Posted by robert sylvester on Monday, January 14, 2013 1:35 PM

MCLEVELAND:

I have the same problem with a new BLI steamer. I run DC but I was told that the DCC sound and BLI  locomotive would run on my DC.

The sound comes on and sounds great but it take a little extra power for it to move then it really speeds up then slows down and at slower speeds it isn't smooth at all, it jerks, as if it is a struggle to move.

Robert Sylvester, WTRR 

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