Wired up lights(all LED) in my F40 using the USA board using pick up shoe track power voltage. When I reverse polarity the lights go dead. What do I need to add too the circuit to keep the polarity straight so the LEDs see the positive signal no matter which way the polarity is coming in? I want all lights on no matter which direction it’s running.
Does that make sense?
Thanks…it’s probably stupid but I’m not thinking straight these days.
A small bridge rectifier will set you straight. 
Thank you Tony!! I thought so…not sure what too get or how to wire it but I will figure it out…
Track power goes to the two wavy lines. DC output to the LED’s. I’d use a small monolith bi-polar cap across the output. Say .1µf # 104.
Thanks again Tony…