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  1. #1
    Join Date
    Jul 2008
    Location
    Hanover, MA
    Age
    27
    Posts
    92

    Angry First DCC Decoder install: FAILED

    http://www.ppdnmra.com/decoder-inst.pdf

    I followed this link with the Spectrum Dash 8, right down to using the same decoder

    I did do a few things different. Instead of drilling and tapping, I drilled the holes and soldered the power and ground to the holes instead of using a screw.
    Then I sort of reused the light circuit board.
    That circuit looked like this: (the RED things are the "WIPERS" that connect on the chassis to get power and ground)



    Then I modified it to this:

    The "blue" line is the wire that the directions said was the common and the "green" lines are each bulbs power according to the directions (Obviously the colors are not exact!)

    All went well. Put it back together but didn't put the shell on, put it on the track in DC mode. It wouldn't move unless I turned the motor then it would spin a bit and then stop. The rear light worked but not the front. I got it move a short distance so I put the DCC Control to "3" and it did the same thing. Would go a short distance and then just stop. Would only go "forward." Then after a bit of fiddling it ceased to do ANYTHING. The rear light would go on when I put the controller into "Reverse" but the front light wouldn't do anything and nor did it ever.
    Even if I turned the motor a bit, it still wouldn't move. So I gave up and took the decoder out and desoldered everything and essentially gave up.

    Does anyone know what I did wrong? It would be greatly appreciated, I would like to order the same decoder and give it a shot again.

  2. #2
    Join Date
    Dec 2008
    Location
    Edmond, OK
    Posts
    348
    are those LED's or bulbs? if they're LED's, then the way you split that circuit you've got one light hooked up with backward polarity, the front one from your description.

  3. #3
    Join Date
    Jul 2008
    Location
    Hanover, MA
    Age
    27
    Posts
    92
    Ya know, I didn't even think of that. It's at my buddy's house now.
    It's from 1995 so I'm not sure if that helps in deciding whether it's a LED or incandescent.

  4. #4
    Join Date
    Jun 2004
    Location
    Austria
    Age
    51
    Posts
    455
    From the pdf it looks like there are incandescent lights in this loco.

    To help you finding the error the next step would be to connect only the motor and disconnect the lights. I always do it that way.
    Then test the loco on the tracks without the lights connected.
    If the motor works than we need to look deeper into your wiring.

    hth
    Michael

  5. #5
    Join Date
    Jul 2008
    Location
    Hanover, MA
    Age
    27
    Posts
    92
    My friend is going to build me the decoder tester at the end of the write up :D

  6. #6
    Join Date
    Jan 2007
    Location
    Christiana, TN
    Age
    43
    Posts
    833
    From the PDF, it does look like the lights are incandescent bulbs; however, it also looks like the light board has diodes on it to make the lighting directional, which is causing the same polarity problem as the LED's would. If this is the case, I would remove the diode for the front light, reverse it, and reinstall it. You could just place a jumper wire around that diode, but the diode will cause a voltage drop which will extend the life of the bulb.

  7. #7
    Join Date
    Feb 2010
    Location
    Westminster, MD
    Posts
    331
    Try hooking up the motor and decoder with neither one installed in the locomotive. Take clip leads and attach the red and black wires to the rails and attach the orange and gray to the motor. See if the motor will run and reverse. If it doesn't, either the decoder or the motor is bad.

    If the motor runs without being installed, try installing the motor in the locomotive but still using the clip leads to connect to the rails to the red and black wires. If the motor doesn't work this way, you've probably got a problem with the motor leads touching the frame.

    Next try connecting the red and black wires to the locomotive body. You said you soldered the leads directly to the frame previously. Depending on what size soldering iron you are using you may be getting a cold solder joint. Try making the connection with the clip leads first, if this works try making the solder connection again and see if it still works.

    If everything works to this point mount the decoder to the locomotive making sure that the underside of the decoder isn't touching the frame.

    Now get the lights to work. I think CSX Robert's post explains why the lights aren't working.

  8. #8
    Join Date
    Jul 2008
    Location
    Hanover, MA
    Age
    27
    Posts
    92
    Quote Originally Posted by markwr View Post
    Try hooking up the motor and decoder with neither one installed in the locomotive. Take clip leads and attach the red and black wires to the rails and attach the orange and gray to the motor. See if the motor will run and reverse. If it doesn't, either the decoder or the motor is bad.

    If the motor runs without being installed, try installing the motor in the locomotive but still using the clip leads to connect to the rails to the red and black wires. If the motor doesn't work this way, you've probably got a problem with the motor leads touching the frame.

    Next try connecting the red and black wires to the locomotive body. You said you soldered the leads directly to the frame previously. Depending on what size soldering iron you are using you may be getting a cold solder joint. Try making the connection with the clip leads first, if this works try making the solder connection again and see if it still works.

    If everything works to this point mount the decoder to the locomotive making sure that the underside of the decoder isn't touching the frame.

    Now get the lights to work. I think CSX Robert's post explains why the lights aren't working.
    This is just what I am looking for, thank you! I bought another decoder and will try this when it gets here. The motor works no problem when attached to the track with wire leads in both directions.
    And I should have the decoder tester next week.

  9. #9
    Join Date
    Mar 2009
    Location
    Massachusetts USA
    Posts
    925

    Decoder tester

    more info
    Quote Originally Posted by GarrettSE View Post
    My friend is going to build me the decoder tester at the end of the write up :D
    Be advised, I found this decoder tester info on the Internet. The idea is someone elses.

    I am including some photos of my simple decoder tester. The bi-polar LED indicator works but I preferred a motor. The decoder is an older SoundTraxx LC decoder. I attach the leads from my NCE Power Cab to the two leads on the blue terminal block. The blue terminal block came form Radio Shack.

    I used a 8 pin NMRA connector mounted on standoffs on an old plastic project box. Nothing in the box except some wires to the motor.
    I removed the 120 ohm resistor, 1 k resistor and bi-polar LED. I grabbed a can motor out of an old CD burner form a cast off PC.
    I put a flywheel with diagonal black marks on the motor shaft to get an idea of decoder/motor action.
    If your decoder has the 9 pin JST connector, DCC on line companies sell a 8 pin to 9 pin adapter.
    If the decoder only has wires, I solder the wires to another 8 pin NMRA connector and plug that connector into the one on the tester.







    Rich
    Last edited by lexon; October 15th, 2010 at 05:03 PM. Reason: more info

  10. #10
    Join Date
    Jul 2008
    Location
    Hanover, MA
    Age
    27
    Posts
    92
    Just out of curiosity, where in MA are you? I'm on the South Shore.

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