Cannot get lights to work

[Blueleader]

Well I installed an LM-3S on a BLI Centipede today and cannot get the lights to work. It was DCC and I pulled the board and did a hard-wire. Sounds and movement all work perfect but no lights. I followed the Ring diagram and put the blue wire common to the grounds on the LED's. I ran 1K resistors in line with outputs 1,2, & 3 to the positive of each LED. The Centipede made it around my helix great but I have 2 track elevation changes that it doesn't like and the front and rear trucks lift all 16 drive/pickup wheels off the track just enough to stop it...Time to call out the MOW team. Any help appreciated on lights.

[Alan]

The blue wire is positive. The module outputs are ground when on.

[Blueleader]

So unlike usual installs where the resistor goes on the positive of the LED, here it goes on the ground?

The blue wire is positive. The module outputs are ground when on.

[William Brillinger]

Have a look at the wiring diagram at the bottom right of this PDF:

www.ringengineering.com/RailPro/Documents/LM-3Instructions.pdf

[Alan]

So unlike usual installs where the resistor goes on the positive of the LED, here it goes on the ground?

The blue wire is positive. The module outputs are ground when on.

The resistor can be on either positive or negative. It is common convention to put the resistor on the positive side but electrically it doesn't matter.

[Blueleader]

Thanks for the help! I reworked the wiring and tested the factory board the head, # boards, and cab lights were mounted to and found a faulty connection on the # boards. So I bypassed the board and all lights work great. I can even strobe the cab light 

[Carter]

The BLUE is positive and the Green and Violet are grounds. What are or is the LM-3 voltage output on the Blue wire? AND which wire Green and Violet are for the Front light and the rear light? Wiring diagram needs more detail.

[G8B4Life]

Carter,

Technically the front and rear headlights would be wired to the white and yellow wires on the 9 pin harness. This follows the DCC standard for 9 pin plugs, and if you use the auto reverse headlights feature it only works on those two wires. You could wire up your headlights to other wires if you wished, that's your choice but most people stick with the standard white and yellow.

The voltage on the outputs is about half a volt less than the track voltage so if your using a PWR-56 which put's out 14v to the track then the outputs in the LM will put out roughly 13.5v.

- Tim

[Carter]

Tim thank you. I assumed  (I know the saying) that the Green and Violet where the head - stern lights. And that the "common" was the ground.

Goes to show that relying on standard terminology can get you in trouble. The difference between hard wire engineers (me) and electronic engineering Ring. Same as the Mars Explorer one group used metric and the other group used feet and inches.

Carter

[Alan]

... The difference between hard wire engineers (me) and electronic engineering Ring.
Carter

So true. It has confused more than one person.

Residential, commercial, and industrial wiring normally switch everything (contactors, controls, lamps, etcetera) to the positive rail. Electronic devices switch everything to the ground rail. There are sound reasons for this difference. In the former it is safer for people to be isolated from the positive rail. Electronics have no such people safety concerns and so are optimized for operational speed, cost, and size. NPN semiconductor devices (switch to ground rail) are faster than PNP semiconductor devices (switch to positive rail). NPN devices are also physically smaller than PNP and as such take up less space and are less expensive to manufacture.

Your fun fact for the day!

[Carter]

Alan thanks very much. I study electronic but not enough, electrical systems on boats, marine craft as a designer (hard Wire) circuits.

Here is one of my RaiPro conversion using the factory light circuit board.  Thank you for your help.

Carter

https://rpug.pdc.ca/index.php/topic,537.0.html