Buzzing N scale engine : LUSENET : Wiring for DCC : One Thread

I have just purchased a MRC Prodigy DCC system and intend to use it to operate my N scale layout (3'X8'). I placed a decoder ready Atlas SD-60M engine on the track and attempted to test it. It made an awfully loud buzzing sound which quieted somewhat when I advanced the throttle. I was using the standard address to control my engine. When I eventually install a decoder will the buzzing go away? Or will I always have to put up with it? It really isn't what I would like to hear while my engines are all idling! Any advice would be appreciated.

Dustin Pendergast

-- Dustin Pendergast (, November 28, 2002


I had the same problem withone of my SD-60M. I am also using a Prodigy DCC system. What I found was the motor lead next to the fram sometimes grounds itself out on the frame. I took the decoder out and put a piece of tape on the frame. Reinstalled the decoder and the problem went away.

-- Wolfgang Neumaier (, November 29, 2002.

If I am reading your question correctly you are referring to the buzzing sound in a non-decoder equipped but decoder ready engine right? The sound you describe is normal and will go away once a decoder is installed.

-- Joe Maxey (, November 30, 2002.

Hi Joe.

Wolfgang was correct. In DCC the motor connection have to be completely isolated from the rails, otherwise a DCC decoder gets instantly destroyed! Even if the installation is correct, on some engines You may hear a humming noise at slow speeds if the decoder doesn't drive the motor at high frequency. A quiet decoder drives the motor at 16kHz, which is past the human hearing range. Zimo decoders uses 32kHz for absolute quiet running engines! If You want to check them out go to:


-- Art Luescher (, November 30, 2002.

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