I have a set of commuter cars and locomotive set up for push-pull operation. I would like to set up the lighting on the loco and cab car realistically. The loco is easy, but I am uncertain on how to wire the cab car so the headlights and taillights work properly, based on running direction. Do I need to put a decoder in the cab car? If so, do I need a jumper or resistor between the motor leads on the chip to complete that circuit? Or do I (arg) need to wire the loco and cab car off the same chip? I welcome any advice, links, etc. on how do do this.
TIA
Tom
If the cab car is not powered - best bet is probably to use a lights-only decoder like one of the TCS FL’s. If the set always stays together, give it the same address as the motor decoder in the power car and it will be very easy to get the lights to work properly, setting the lights in the power car to be off when in reverse and the lights on the cab car to be off in forward.
–Randy
If the train always stays together, you could just run a long pair of wires from the loco back to the cab car, wiring the cab car as if it were the rear headlight of the loco. This could be awkward at times, so a couple of small plugs and jacks in the line would help.
In the long run, though, I think you’d be happier with a decoder.
One of the Brit magazines last year had an article on adding DCC to a six unit MU train (one of the European ones) where the power cars are in the middle. I think he ended up with at leat 3, possibly 4. different decoders.
Motor+lights for the powered units. Lights only for the cars. Lights + headlights /class lights for the end cars.
I just wanted to bring this to the top again in case anyone has an idea for doing this with a motor decoder. I have one or two decoders that I “smoked” due to poor soldering ability, but the light functions still work. Is there a way to bridge the motor outputs without a motor to make the chip funtion without a motor?
Yes, you need a resistor. About 100-150 ohms, 1 watt. You can get away with less if you set the decoder up for a speed table or set the start volts to 0, mod volts to 1, and top to 2 so the motor output always stays low.
You really only needs this for programming - the decoder will run fine with nothing connected to the motor leads. Do NOT short them together, rather insulate them so they touch nothing. It will take programmign commands but be unable to ackowledge them or read back CV values with no load on the motor terminals. You could just jumper them to a spare motor for programming and then disconnect for operation.
–Randy