install decoder on Bachmann 4-8-2

Discussion in 'DCC & Electronics' started by Wiredup, Feb 14, 2008.

  1. Wiredup

    Wiredup Member

    Hey all,
    Recently I've been trying to convert my Bachmann Spectrum 4-8-2 lt. Mountain to DCC operation.

    I have a pair of DZ143 decoders that I purchased, and both have gave me the same issue with the loco...the first started smoking and now has some charring on the wrapping of the decoder. I believe it's a burnt component...

    I installed both decoders based on the instructions found here Install DCC Decoder in Bachmann USRA Light 4-8-2 and used the first method for controlling the headlamps (white to blue, blue to white...because apparently bachmann wired it reversed.)

    What both decoders do when the loco is set on the tracks (using a Bachmann EZCommand DCC controller) it starts making a sputtering noise, the controller starts flashing (as if there is a short circuit) and the headlight flickers. Throttle set to 0

    This is where the first decoder burnt up. The second one didn't burn up or start smoking, or even smelling like smoke, but I also unplugged the track ASAP.

    The second decoder during install didn't flicker the first time I wired it up. The headlight did function properly according to the decoder (switched to address 3, and then used the function command to turn the light on and off) loco would not move, or even attempt, even if I gave it a lil helping push.

    After resoldering the wires on the theory of a cold solder joint, the loco started to flicker.

    Out of curiousity I took the second decoder and installed it in my Model Power Pacific... low and behold, it runs perfectly first try. So I'm convinced that I am either doing something wrong, using the wrong decoder, or my loco is a bit funky in the not working department.
  2. MasonJar

    MasonJar It's not rocket surgery

    DZ series are Z scale decoders I believe. Perhaps your particular 4-8-2 is pulling too many amps for the decoder to handle? Do you have the ratings for both your engine and the decoder? Or did you test the engine as per the Digitrax decoder instructions?

  3. nkp174

    nkp174 Active Member

    If they are charring, connect an ammeter (or a multi-meter) to the track and press down on the locomotive until it stalls (with all the bells & whistles on). That's the maximum current draw. If it is higher than the decoders specs say it will handle...then it'll fry that decoder every time. It is the same thing as making sure you use an adequate size wire for electricity...a 20amp circuit running through a phone wire will fry the wire in seconds...too much current
  4. rogerw

    rogerw Active Member

    Its rated at 1.25 cont. /2 amp peak, I would think that should be ok. I have a question on running all the bells and whistle ,They dont go through this decoder ,do they?I would think just the motor goes through this decoder.
  5. Wiredup

    Wiredup Member

    motor and headlights are run through this decoder. this decoder is the one I see recommended for this loco on many websites, so I would hope it would work okay.

    Never tested the engine per digitrax instructions...

    I may go a pickup a lenz decoder to see if it will work...
  6. rogerw

    rogerw Active Member

    Get a TCS decoder that way if it fries they will replace it.

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