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Fitting a Decoder to a Tomytec Chassis

Geoff runs OO9 (OO narrow gauge – runs on n gauge track) and asks readers:

“I am trying to fit a decoder to the Tomytec chassis TM-07R.  The chassis works fine on my DC test track, and the decoder is fine on my decoder tester.  But when I put the two together, everything is fine at first, then after a few minutes it slows to half speed, then it randomly starts and stops, and then it goes to full speed, at which point it doesn’t obey commands to slow down, and I have to use the emergency stop button.

I’ve tried with two different chassis, and two different decoders (same brand), same result.  My system is the NCE Powercab with their SB5a booster.  All my other DCC locomotives (that were fitted with decoders at the factory) work fine.”

2 Responses to Fitting a Decoder to a Tomytec Chassis

  • Nigel says:

    I’m not acquainted with the Tomytec chassis but I had a similar issue with Hornby chassis when I fitted decoders myself – erratic speed and uncontrollable. It turned out to be the suppression capacitors and after I removed them, everything worked fine.

    On the basis that both your chassis and decoders work fine when not connected to each other, logic suggests that it has to be another component. On the basis that, in its simplest form, a DCC decoder connects directly to the track through the red and black wires and directly to the motor through the orange and grey wires, anything else that enters the signal path, so to speak, may well be the issue so I’d definitely suggest having a poke around to see if there are any hidden components screwing things up.

    I hope this helps and good luck!

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