Did I fry my decoder?

prr2bnsf_sd Jul 16, 2020

  1. prr2bnsf_sd

    prr2bnsf_sd TrainBoard Member

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    I was trying to install a TCS EUN651 in my FVM GP60M and was confused by the documentation which side was supposed to face upward. I inserted the direction that seemed most likely from the TCS tutorial for the FVM ES44.

    When I placed the locomotive on the track to test it, the lights came on, responded to direction changes by not F0, and the locomotive would not move. I tried flipping the decoder and reinserting it, and this did not help. Then, at some point in the process of trying both sides, I saw a puff of smoke come up from the decoder.

    Fortunately, the engine still runs on DC. Is the decoder fried though?

    Edit: Engine will no longer move with DC track power. Will move and light-up when voltage applied directly to motor pickups, though. Not sure what that is about. Voltmeter says that current can flow through rail to motor pickups.

    Edit #2: My wife helped me realize that the light board was just making poor contact with the frame. Runs fine on DC again after adjusting the position of the light board.
     
    Last edited: Jul 16, 2020
  2. RBrodzinsky

    RBrodzinsky November 18, 2022 Staff Member TrainBoard Supporter In Memoriam

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    Smoke coming out = fried decoder

    TCS has a good warranty exchange program
     
  3. prr2bnsf_sd

    prr2bnsf_sd TrainBoard Member

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    Ugh, fantastic. I was so excited to get the locomotive running, too...
     
  4. rray

    rray Staff Member

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    DCC = Smoke Happens Eventually! I have smoked a dozen or so decoders over the decades. I have also repaired smoked decoders. It's always the same, the H Bridge or MOSFET's that burn out. Tiny, and not fun, but if you have the skills, you can repair them. The older larger HO and N sized decoders are easiest, but the newer tiny Z Scale ones are too hard to repair for me.
     
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  5. dalebaker

    dalebaker TrainBoard Member

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    Robert- I strongly identify with the first portion of your post, strongly......:ROFLMAO:
     
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  6. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    Here is a drawing for the EUN 651 from the TCS website. On the decoder, there should be a small gold triangle that denotes pin 1 (orange). You can see it below the bottom pin in the photograph of the decoder. I don't model N scale, but there should be some kind of marking on the FVM board. Usually it will have a matching triangle on pin 1. The marking on the decoder should be on the same pin as the board when you connect them. You can contact TCS for a warranty or repair, but it definitely sounds like the decoder has become damaged.

    EUN651 Diagram.jpg TCS-Decoder-EUN651-121355850647.jpg
     
  7. prr2bnsf_sd

    prr2bnsf_sd TrainBoard Member

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    Got news yesterday that I did indeed manage to fry the decoder, so the new one is in the mail from TCS now. Thank you for pointing this out, I had not seen this and hopefully it will make my next attempt go better.
     
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  8. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    It's good that you got a replacement from TCS. It sounds like it may have been in the correct orientation the first time when the lights came on, but it is strange that the other features did not respond correctly. Maybe the decoder was bad from the factory and was going to blow anyways.
     
  9. CSX Robert

    CSX Robert TrainBoard Member

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    FYI - Just plugging the decoder in backwards, unless that somehow causes the decoder to contact the frame, will not fry it (however it will run backwards), so there must be something else going on. If the decoder itself was not defective, there must be a short somewhere so make sure you check that out before trying the replacement.
     
  10. prr2bnsf_sd

    prr2bnsf_sd TrainBoard Member

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    Huh, ok. The loco runs fine on DC now, although occasionally has issues with the light board not contacting the frame. How else would I check for a short?
     
  11. prr2bnsf_sd

    prr2bnsf_sd TrainBoard Member

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    I am very happy to report that I got the replacement decoder today and everything works! Thank you for the help everyone
     

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