led flasher help

Check out this place, they have  exactly what you want.

http://www.modeltrainsoftware.com/bl-213-f.html

Marty

Seems the expedient solution is to buy the flasher in Marty's link.

But if you want to figure it out for yourself, do you have a diagram or link to what exact hookups you tried?  My first thought was you need more capacitance in your circuit but a schematic/diagram would confirm that.

It sounds like you are using variable AC track power for the loco and thus the LED flasher(?).  Is this a case where having a buck-boost circuit (along with a bridge rectifier) would provide the stable DC voltage needed for the flasher?  I don't know how sensitive they are to input voltage, but it sounds like the current draw through the motor drops the voltage enough to make the flasher inoperable.

As has been discussed recently on other fora, there are buck-boost boards available on eBay for very little money and they have adjustable voltage outputs.

Here's a simple circuit that will do the trick and regulate it properly for most any track voltage from around 5 volts and up.  I'd pick a resistor of 75-80 ohms for the flasher.  Since this is a constant current circuit, you don't have to worry about the exact operating voltage of the flashing LED.

Do these flashing LEDs draw a fixed current (when on and off)?  I'd think some would draw less current when off, more current when on.  IF such is the case then a constant current circuit will attempt to force the programmed current (16mA using your suggested R) by increasing the voltage to the LED when the LED is off.  This voltage could go above 20V with command voltage on the track.  I'd think there might be an issue with maximum allowed voltage to the LED or perhaps power dissipation in a tiny LED with >20V and 16mA going into it.  In my opinion of course!

I've powered them with the CL2, but that's an interesting question.   They do draw less when they're off I would imagine.

This may be a place where the constant voltage would be better. Just sticking a LM7805 in place of the LM317 (with wiring changes of course), and a series 100 ohm resistor would do the trick.  I know you need filtered DC for these, so you have to include a capacitor.