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DCC Installations Problem Track and electrical/DCC
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Regular poster 298 posts akarmani Regular poster 298 posts
akarmani

I am installing a Digitrax SDH164 into a older 2-8-2 steam engine for a friend. I am not really sure what brand of engine it is.  It is an inexpensive engine, but it has a can motor. It runs ok on DC. The start voltage is around 6 volts and the stall amps at full power is .08 Amps (80mA).

The problem I am having is that it runs really slow when the decoder is connected and it can't pull more than one car.  When I tried it the first time, the engine would not even move. To be honest I am not sure what I did to get it to move, but now when the throttle is wide open, the cuff sound from the decoder is going like mad, but the engine is moving along at about one foot every two seconds.  When I remove the decoder and jump the wires to operate on DC, it moves as you would expect and can pull like normal.

Several of us have verified the wiring and we know it is connected correctly. We have also tried more than one SDH162 decoders and it act the same for each one. My original though was that the engine was pulling too many amps for the decoder, but the stall amps are only .08 Amps and the decoder is not getting hot.  I thought this decoder could handle 1 Amp.  A front and rear headlight (operated one at a time) is the only other thing connected to the decoder.

 The only thing I have done to the CVs is turn off the Supersonic CV9=255 and turn off the BMF CV57=0.  It does not appear to have any effect as I have factory reset the decoder and the problem does not change.

Any ideas?

Art
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Prof_Klyzlr Moderator 7,942 posts
Prof_Klyzlr

Speed Step mode?

Dear Art,

1 - What speed step mode (14, 28, or 128) is the DCC control system set for?

2 - What speed step mode is the decoder set for?

3 - What are the values of CV2, CV6, and CV5 (in that order)?

4 - if available, what is the "Track Output Voltage"
(may be listed as "scale" on the booster)
set for?

Happy Modelling,
Aim to Improve,
Prof Klyzlr
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akarmani Regular poster 298 posts
akarmani

I will check

Prof Klylr,

I am not sure what speed step mode the DCC was set for.  I think it was set to 128 steps.   I will check it as soon as I can.  We are using our club's CVP EasyDCC system.  The Track Output Voltage is set for HO and the DCC system is in constant used by several different decoders including the day we tested the engine.  The decoder speed step mode and the values for CV2, CV6, CV5 are at the factory settings for a Digitrax SDH164.  Factory setting for CV2, CV6, CV5 are 000.

Art
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Prof_Klyzlr Moderator 7,942 posts
Prof_Klyzlr

Dear Art, Um,  CV2 = Minimum

Dear Art,

Um, 

CV2 = Minimum voltage (SS1)
CV6 = Mid voltage
CV5 = Max voltage (SS28 in 28-step mode)

If these 3 CVs are set to zero, either the decoder is using a custom speed table
(which would potentially completely explain the slower-speed behaviour)

or literally the loco has been told that all speed steps 0 - 28 are "stop"...???

Something is very not-right here...
(How did you read the CV values?)

Happy Modelling,
Aim to Improve,
Prof Klyzlr

​PS not sure if it's relevant, but I seem to recall some posts on the Digitrax YahooGroup about some decoders having oddball/sluggish speed behaviour, particularly when the horn (diesel) was blown. IIRC was related to BEMF Enabled/Disabled...
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akarmani Regular poster 298 posts
akarmani

Still perpelex.

Prof Klyzlr,

I did not read the setting on CV2, CV5, and CV6.  I did a factory reset (CV8 = 8). According to the SDH164D instructions a reset sets CV2, CV5, and CV6 to 000.  According to the Sound Decoder Manual: CV2 = 000 start voltage is zero; CV5 = 000 is backwards compatible with 000,001, and 255 = 100%; and CV6 = 000 the decoder assumes a "straight-line" throttle response curve.

I agree, something is not right here.  Once again I am having the same problem on either decoder tried.

 

I had turned off the BEMF before the reset.  It did not help.  Since I did the reset I am not sure what the BEMF is.

Art

  
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Hardy Dittmar New member 2 posts
Hardy Dittmar

DCC installation into a spectrum selfpropelled ballastspreader

Does anyone know how to instal a DCC decoder into an Spectrum(Bachmann) self propelled ballast spreader. There is very little space to do it. there must be a way because the parts sheet makes reference to DCC but doesn't elaborate. I purchased the unit several years ago. Thanks Hardy
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