Assuming the decoders use the motor as a load to communicate back to the command station (i.e. for reading back CV values) you need to simulate a motor. I don't know if a bulb would be a good simulation for this. Bulbs are basically resistive loads, but have a large inrush current. When first turned on while the filaments are cold, a bulb may take 10 times it's hot current. Motors, on the other hand, are inductive loads, and also have a back-emf which goes up with motor speed. I think I would try a resistor across the motor leads of about 12V/.1A = 120 Ohms. For experimental purposes, how about hooking up a real motor and getting the decoder communicating. The substute a resistor for the motor with a rather high value, maybe 220 ohms, and reduce the resistor value until the decoder will communicate. I wouldn't go lower than 68 ohms or so. If you try a bulb, make it a much lower current one, like 12V 30ma. That should not pull much more than .3A at startup.
Jim
I am still designing my experimental stationary sound system using Soundtraxx DSXs and LCs (just now awaiting arrival of correct transformers in the mail)
I have heard that the LC series decoders (not usually used as stationary) may require a motor load to respond. A light or resistor would do this. I would like a light to signal the decoder in use on the sound board I am making.
What voltage and mA would be best?....one close to the lighting used by the decoder (1.5 V) or higher in voltage? I am going to put the bulbs in Radio Shack E-10 bases (as I have nothing like a socket for the grain of wheat sizes) so this gives me a choice of these Radio Shack bulbs:
2.5 V & 300mA7.5 V & 220mA14 V & 200mA2.5V & 360 mA14.5 V & 100mA6.3 V & 150mA or 250mA
Soundtraxx is yet to respond. In the meantime, does anyone have a good idea?
Thanks