Model Railway Forum

Hi there, I have a 2002 piko german steam engine and I would like to fit a DCC chip in it.However there is a "choke" fitted below the motor, can I still fit a chip, can I discard the choke assembly, where should I connect my chip (orange/grey) motor wires to.
Any help or advice greatly appreciated.

Chokes do not cause any issues. Its capacitors that can do!
If you can, connect the decoder Grey and Orange wires directly to the motors connection after removing any factory fitted motor wires. There must be no connection between any motor terminal and any wheels. If there is any connection remaining then the decoder will fail immediate on applying DCC power!

Just to add to Brians answer, make sure the loco runs well on DC before adding a decoder.

ok so I disconnected the choke wires,put the red and black decoder wires to the pick ups, the grey and orange to the motor and nothing happens, its as dead as the proverbial parrot.It ran fine on DC power and I tested the chip in another loco and it worked OK...any ideas folks

If you have removed the chokes and the feed to the motor is via these, they need to be replaced by wire links. Otherwise there is no feed path to the motor! Especially if the chokes were on a PCB and you're still using the PCB for feeding
But if you've soldered the decoders Grey and Orange wires directly to the motor then their removal shouldn't matter. I assume you removed all other connections to the motor before applying the grey and orange wires if the two decoder wires are soldered direct to the motor. Including checking there is no physical connection to either motor tab - chassis connection etc?

Chokes are in series with each motor feed while capacitors are in parallel across the two feeds!

thanks Brian ,heres the progress so far, removed the chip and all wires, removed motor,it runs fine on its own, reinstalled motor, loco runs fine on analogue,altered wiring to refit chip,when its on the track the motor buzzes for about 10 seconds, the motor does about 1 turn and then nothing, I suspect the motor is drawing current but when it gets excessive the chip cuts out?.
thanks again

If your Decoder is directly soldered to the two motor tabs and there is no other connection to these, then it is possible the decoders overload device is operating. What make of decoder is being used?? Do you know its motor rating current (Amps)? Are you able to carry out a DC current running check on the loco?