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Broadway loco will not start off at a slow crawl

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  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Wednesday, July 25, 2018 4:50 PM

 If it's the old QSI decoder, they actually had different operating modes you could select from. There was a perios of time when at least one of the modes was disabled because of the MTH lawsuit, but that was the one where each speed step corresponded to 1smph. Enabling and adjusting the BEMF should get it to run better, and closer to the Loksound.

                                       --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
    March 2017
  • From: Orange County, NY
  • 35 posts
Posted by sktrains on Wednesday, July 25, 2018 1:43 PM

 Ill definitly play around with some of these suggestions and see what happens 

Thanks 

Steve  

  • Member since
    February 2005
  • From: Vancouver Island, BC
  • 23,321 posts
Posted by selector on Tuesday, July 24, 2018 9:12 PM

There might be CV's to vary BEMF sensitivity, dither, torque/boost, and esoteric stuff like that on the QSI.

http://www.girr.org/girr/tips/tips10/qsi_tips.html

 

  • Member since
    February 2002
  • From: Mpls/St.Paul
  • 13,776 posts
Posted by wjstix on Tuesday, July 24, 2018 2:36 PM

Yes, I always speed match for the normal operating range of speeds first, then usually not that hard to fine-tune starting and stopping together...often just need to use momentum CVs 3 and 4.

Stix
  • Member since
    December 2004
  • From: Bedford, MA, USA
  • 21,342 posts
Posted by MisterBeasley on Tuesday, July 24, 2018 1:08 PM

I had a similar problem with a Bachmann engine with a Sound Value decoder which doesn't recognize Vstart.  I reduced Vhigh (Vtop?) because I never ran anything that fast.  This reduced the step voltage and eliminated the jackrabbit start at speed step 1.

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

  • Member since
    February 2002
  • From: Mpls/St.Paul
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Posted by wjstix on Tuesday, July 24, 2018 1:03 PM

There's no reason you can't speed match the BLI and Loksound (I assume that's what you mean by "lock sound decoder"....in German "locomotive" is spelled with a k - "lokomotive" - so it's pronounced like "loke-sound") decoders. It's more than just CV2 however. For smooth joint starts, you often have to adjust CV3 (and CV4 for stops). Also, make sure both engines are using a straight-line speed curve, and that you've already used CV 5 and 6 to speed match them at normal running speeds.

FWIW real diesels generally rev up their engines before starting to move, so it often is more realistic with sound-equipped models to set the CVs so the engine doesn't start right at step 1, but has a change to rev up the motor sound first before the engine starts to move at a higher speed step.

Stix
Moderator
  • Member since
    June 2003
  • From: Northeast OH
  • 17,200 posts
Posted by tstage on Tuesday, July 24, 2018 12:12 PM

Baron's correct, Steve.  Loksound has much better motor-control than the Quantum decoder.  If you want to match slow, go with another Loksound decoder.

Tom

https://tstage9.wixsite.com/nyc-modeling

Time...It marches on...without ever turning around to see if anyone is even keeping in step.

  • Member since
    January 2015
  • 257 posts
Posted by RR Baron on Tuesday, July 24, 2018 12:00 PM

Speed matching BLI to Intermountain at slow speed not going to happen. You will have to speed match Intermountain to the BLI, which you will discover is difficult. 

Want to speed match  - replace the Quantum with LokSound. 

 

RR Baron

  • Member since
    March 2017
  • From: Orange County, NY
  • 35 posts
Broadway loco will not start off at a slow crawl
Posted by sktrains on Tuesday, July 24, 2018 11:43 AM
Hi all
Im trying to speed match a Broadway  sd40-2 with a quantum decoder to a intermountain sd40-2 with a lock sound decoder, the intermountain starts off at a real slow crawl at speed step 1 and increases nice and smooth from there hence why I’m trying to match to that one. But the problem is I cant get the Broadway to start at a slow crawl at speed steep 1.
I have adjusted the start voltage CV ranging anywhere from 0 all the way up to 60 and a bunch of combinations with the speed step 1 cv  and what I get is, it won’t even move at speed step 1 unless the start voltage CV is at at least 55 (32 is the default) but  then when it does go its faster than a crawl
Any thoughts or suggestions would be greatly appreciated

Thanks 

Steve 

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