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Bad decoder?

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  • Member since
    July 2008
  • 1,206 posts
Posted by mfm37 on Friday, December 25, 2009 11:24 AM

 Don't ever connect the orange and gray wires of a decoder to DC, AC or any other type of power. That's the same as shorting them to the rails and will instantly fry the motor outputs on the decoder. If testing a motor, disconnect the decoder before applying power to the motor. Fortunately my first encounter with this mistake was with a "goof proof" decoder. The replacement was free.

Martin Myers

  • Member since
    July 2003
  • From: Sierra Vista, Arizona
  • 13,757 posts
Posted by cacole on Friday, December 25, 2009 10:12 AM

cudaken

 Will test the motor to see what amps it pulls now. Maybe install the stock board and try it on DC.

 

 

The motor can easily be tested without any circuit board -- just connect the gray and orange wires from the decoder to a DC power pack.  Turn the loco upside down and run it.

  • Member since
    June 2006
  • From: Maryville IL
  • 9,577 posts
Posted by cudaken on Friday, December 25, 2009 10:05 AM

 Thanks for the answer. Next I pull a part the F-3 and see what I can find. Will test the motor to see what amps it pulls now. Maybe install the stock board and try it on DC.

 Hope it something simple, I run the F 3's a lot. This maybe the first Proto I have gone bad.

       Cuda Ken 

 

 

I hate Rust

  • Member since
    December 2001
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Posted by Stevert on Friday, December 25, 2009 9:52 AM

cudaken

 My real question was "if the decoder is bad, would Decoder Pro be able to read all the CV's"

 

Ken,

  Yes, it's certainly possible that the motor drive circuitry could be blown in such a way that it can't run the motor smoothly (or at all), but is still able to provide the acknowledgement pulses needed for CV readback.

  Since it seems that the same loco did that to two different decoders, I'd carefully check that loco for shorts, excessive current draw, etc. 

HTH,
Steve

  • Member since
    July 2003
  • From: Sierra Vista, Arizona
  • 13,757 posts
Posted by cacole on Friday, December 25, 2009 9:51 AM

 Yes, Decoder Pro could still read CVs if the decoder is bad, depending on what within the decoder is bad.  Usually it's the motor drive that goes bad, but the CVs can still be read because they are within a different microchip than the motor drive circuitry.

 

  • Member since
    June 2006
  • From: Maryville IL
  • 9,577 posts
Posted by cudaken on Friday, December 25, 2009 6:30 AM

 My real question was "if the decoder is bad, would Decoder Pro be able to read all the CV's". I am not to the point of trying to figure out why the engine does not run, or what is causing the problem.

 Thanks for your kind answer anyway.

                      Cuda Ken

I hate Rust

  • Member since
    May 2009
  • 356 posts
Posted by Silver Pilot on Friday, December 25, 2009 5:02 AM

cudaken

 For the heck of it, tested it with Decoder Pro, it read all CV's? I thought when a decoder died, Decoder Pro would not read CV's, am I right? I will try to read the first decoder (DH 163) and see what happens.

 I will open the F-3 and see if the 9 ping plug is tight and all the wires are hooked up right.

         Ken  

How about doing these things first and telling us the results before posting the original thread and wasting everyone's time guessing what might be the problem.

Google is good! Yahoo is my friend.
  • Member since
    June 2006
  • From: Maryville IL
  • 9,577 posts
Bad decoder?
Posted by cudaken on Thursday, December 24, 2009 7:16 PM

 OK, I have not melted a decoder in 9 months. Remember the old days when I pulled out a blacken mess? Big Smile

 About a month ago, one of my Proto 2000 F-3 stopped running. It had a Digitrax DH 163 (go figure it was a more expanse one) and I ran the 4 F-3 MU a lot! As with most of my engines well over 200 hours. As it was giving up the ghost, it would move, stop, move, stop till the point it would short out the DCC system. I pulled the decoder and installed in a PK 2000 SD 7, sat it on the track and it shorted out the DCC system again. OK, decoder is dead, but it led a good long life.

 Installed anew DH 123 in the same PK F 3, it ran but was not speed match to the other F 3's so it sat. Tonight I decide to speed match it. Set it on the track, it moved, then stopped, moved then stopped again? Hum, must be something wrong with the engine. Pulled the F 3 then sat it back on the track, changed the direction (I run it backward) light came on, but would not move.

 For the heck of it, tested it with Decoder Pro, it read all CV's? I thought when a decoder died, Decoder Pro would not read CV's, am I right? I will try to read the first decoder (DH 163) and see what happens.

 I will open the F-3 and see if the 9 ping plug is tight and all the wires are hooked up right.

         Ken  

I hate Rust

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