Broadway loco will not start off at a slow crawl

[sktrains]

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 

[RR Baron]

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

[tstage]

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

[wjstix]

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.

[MisterBeasley]

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.

[wjstix]

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.

[selector]

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

 

[sktrains]

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

Thanks 

Steve  

[rrinker]

 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