Coach lights on Hornby APT

[zoomer1979]

Hi there, looking for some advice about using the Aux 2 purple wire to control the coach lights on the Hornby APT. Plan is to use the chip in the DTS and wire down through the other trailer cars X 4. Is it ok to use this for 5 sets of coach lights? Would there be a load issue? Also, would it better to switch the red positive or the black negative. I've only tried switching through the black, as the purple read as -8v DC. Any advice would be great.

 

Neil.

[RAF96]

Most decoders have blue as a common positive, with the function wires (white, yellow, green, purple, et al as floating negatives until selected whereupon they become a true negative for that circuit. Functions normally run at 12vdc with a 100mA limit per function. Some decoders offer a higher limit. Decoders with more than four functions may have logic level outputs or amplified level outputs on functions 5, 6 or higher. See your decoder spec sheet.

Edit - assuming we are talking about an 8-pin decoder, red and black are the track feeds with orange and grey to the motor.

Edited May 18, 2022 by RAF96