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Starting voltage-Older locomotives

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  • Member since
    January 2008
  • 595 posts
Starting voltage-Older locomotives
Posted by mreagant on Wednesday, December 1, 2010 3:57 PM

I have several older locomotives, mostly Athearn, with decoders-- not sure which brand/model in some cases-- and they all need a pretty good kick to get moving; sometimes as high as 10 on a 28 step setting.  I just did a read back on one to see what CV2 was set at, and got 000. 

Questions are, 1.)  could that be a correct  starting voltage setting, and 2.) what should it be to get a more realistic launch?  This particular locomotive is a SW-7 so I'd appreciate any suggestions for other CV settings to profile switcher performance.

Thanks

Mike

  • Member since
    February 2005
  • From: Vancouver Island, BC
  • 23,330 posts
Posted by selector on Wednesday, December 1, 2010 5:29 PM

QSI decoders are factory set (or used to be) with a value of about 35.  I have modern Tsunami and others that don't appear to take any setting.  But in your case, I would assign an initial value of about 50, test, on first speed step, and if it moves off a bit too smartly, halve the 50 and check again.  Then halve that difference until you lock in on a reasonable value.  That's an old method for calling down artillery, by the way.  You estimate, add or drop 400 yards, add or drop 200 yards, and so on until you see the effect you want.   It should also work for this guesstimating process.

If I had to bet, you'll be nearer to 74 before you end up happy.

 

BTW, are your engine shells hot after a while?  Your decoder may get a tad warm drawing all the current it needs to keep both the motor running and the trailing cars moving.

Crandell

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