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CV question

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CV question
Posted by hwolf on Tuesday, December 19, 2017 2:12 PM

I just received a Bachmann Spectrum 50 Ton Climax back from Bachmann.

When I set it to Foward it goes in Reverse and Reverse goes Forward.

I got a copy of thr CV chart but do not see the CV to make these correct.

Which CV's do I change and at what setting?

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Posted by wjstix on Tuesday, December 19, 2017 2:22 PM

Usually it would be CV 29. On most all decoders adding "1" to whatever the value is in CV 29 (so like if it's currently "18", changing it to "19") should reverse the direction of travel.

Stix
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  • From: NW Maryland
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Posted by RRR_BethBr on Tuesday, December 19, 2017 3:52 PM

Stix has you covered! Just note - if you read back CV 29 and it's already set to an odd value (eg: 35), then subtract one, and set CV 29 to that.

If that loco has an 8-pin NMRA connector for the decoder, it's also possible they plugged it in backwards when (re)assembling it for you. I'd be suspicious of that if CV 29 is already an even value, but the loco is running backwards.

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Posted by BigDaddy on Tuesday, December 19, 2017 5:20 PM

hwolf
I just received a Bachmann Spectrum 50 Ton Climax back from Bachmann.

back = another forum mystery.  What did it do or not do that merited a trip back to the factory?

 
 

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by hwolf on Tuesday, December 19, 2017 6:55 PM

It was a different engine with a plastic gear problem ( 70 Ton Climax ).

They replaced it with this one with metal gears.

Harold

 

 

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Posted by hwolf on Tuesday, December 19, 2017 7:04 PM

When checking the CV list for the Bachmann # 29 says

Configuration Register 1 with a setting of 6. Do we look like we are talking the same language?

Harold

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Posted by BigDaddy on Tuesday, December 19, 2017 7:15 PM

So it wasn't an electrical repair where they had to monkey with the wiring.  That eliminates a few possibilities. 

 

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by RRR_BethBr on Tuesday, December 19, 2017 11:02 PM

hwolf
When checking the CV list for the Bachmann # 29 says

Configuration Register 1 with a setting of 6. Do we look like we are talking the same language?

"Configuration Register 1" I guess is Bachmanns name for CV29, But the important thing to know is that CV29 is standard in all DCC decoders. Each of the 8 bits controls a specific setting. A value of "6" would mean that the decoder is in short address (default=3) 28/128 speed step mode, with dc operation enabled. S value of "7" is the same thing, with reversed operating direction.

See here for more info, and a handy calculator:

http://www.2mm.org.uk/articles/cv29%20calculator.htm

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Posted by rrinker on Wednesday, December 20, 2017 9:02 AM

 Calling it Configuration Register 1 is a reference to the earliest days of DCC when you programmed decoders in Register mode, also called Physical mode. There were only 8 registers defined, as early decoders had limited memoery and function. However, the equivalent of CV29 was Register 5. Register 1 was the equivalent of CV 1, the short 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.

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Posted by hwolf on Wednesday, December 20, 2017 2:42 PM

There is no register 5 on the list.  CV 1 shows primary address as the discription and the one next to CV 29 is the register 1. On the list CV 29 is showing a setting of 6. 

If this is the reading I get on CV 29 should I go to a setting of 5 to change it's direction

Harold

  • Member since
    December 2015
  • From: Shenandoah Valley
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Posted by BigDaddy on Wednesday, December 20, 2017 2:52 PM

I think you have to go to 7, the previous posted link was not clickable

http://www.2mm.org.uk/articles/cv29%20calculator.htm

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by rrinker on Wednesday, December 20, 2017 3:36 PM

 Yes, if it's 6, you want to go to 7.

If the number in CV29 is even, then you want to make it the next HIGHEST odd number to change direction (simply add 1). If the number is already odd, you subtract one - make it the next LOWEST even number.

                          --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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