FAQ:What can burn out a decoder?

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DCC Categories Decoder


  • Overvoltage. For example, booster is set to incorrect scale.
  • Current draw exceeds decoder ratings (wiring short or another overload condition). Poor wiring can cause this.
    • Be careful when first testing a decoder installation. Put the vehicle with the newly installed decoder on a test track (programming track or section with a 100-ohm series resistor for current limiting) instead of the mainline for testing. This will limit the current, preventing damage if the decoder was miswired. If all functions work, and the vehicle can move (assuming motor output drive from decoder) at low speed steps, then it should be safe to place it on the mainline. As always, follow the manufacturer's instructions for testing in addition to the above.
  • Overheating
    • Imagine running a black loco in direct sunlight and hauling a heavy load at nearly the limit of the current output of the decoder. Now imagine the decoder only having current limits, and not thermal limits built in. Your imaginary decoder should running extremely hot. As you know, when things run too hot you'll let the magic smoke escape from the decoder. Avoid excessive loads for extended periods of time. If in doubt, check temperatures on newly installed decoders. If you find it running too hot, upgrade the decoder to handle larger currents and/or increase air flow around the decoder.