Hi slipgear, your comment about the resistor in the feed to the lamp is timely as I've been looking at a circuit board in a Spectrum tender. The lamp feed has no less than 5 resistors - 2 x 220K 2 x 470 ohm in parallel and 1 x 1.5K. There are also two diodes and a capacitor. What on earth for? Perhaps to handle the voltage variations when used on a DC layout instead of DCC?