Hi!
I recently started again with model railroading (märklin) but this time all in on digital
I purchased some led lights from Faller and an M84 which is connected to the power from my c track.
The led lights are flickering like crazy though, so Ive tried to understand what is needed to fix it. Do I need to power the m84 with DC power? Is there any circuit track available? Or should I power the M84 with AC power, then power the light with external DC power? I appreciate any tips or help I can get here!

You can try that without harm. Led's can flicker when resistors are not installed between them and the power source. I had that happen often on my old M track layout with a 6021 controller and older Marklin lighted passenger cars with incandescant bulbs even. A standard small 1 m/a-m/v 1/2 watt tan color round resistor with red and silver bands should do fine.

Connecting the 66360 (with or without 60822) to the m84 won't do any good.

If you had an m83 then the 66360 would help to reduce the flicker.

It would help to use power from the 66360 for the LED.

Yes, cycling digital signal, and the LED's react. Can a small capacitor also help? Wether led or incandescant bulbs, they can either use a/c, or d/c current.

It flickers, not because the signal is an alternating current, but because the mfx signal has gaps in the signal which are the periods when the mfx decoder sends its identification signal back to the controller.

If you really need to use an LED then a small bridge rectifier with a capacitor (5-10uF should be plenty I think, use a 35V or greater rating) between the LED and its supply should be adequate. Put these components between the lamp in your diagram and the yellow and brown wires feeding the lamp.

The easiest way to do this is to connect one lead from the power supply to the center set screw connection of say terminal one. Connect the other lead to the ground of the signal. For a 2 color signal the rest is easy, connect the red lead from the signal to the red set screw on terminal one and then green lead to the green set screw terminal. The polarity of the leads is determined by how the led's in the signal are wired. If the signal doesn't light, swap them.

Signals with more than two colors require more than one terminal because either the red or green is always on. In the technical manual for the 60842 (newest M84) there is a mode selection that supposedly give 8 individual outputs but I haven't tried that.

Regards,
Roger

Very late reply here but I've read all your comments which guided me to making it work as I wanted, thanks a lot guys!
I got it working by using an external DC power and moving the previously connected cables from track power to the DC power (according to image).

If anyone is curious I ordered the following items to make it work for me:
https://www.modellbahnsh...95/gb/modell_375984.html
https://www.modellbahnsh...93/gb/modell_375983.html

I also ordered two really tiny (almost non existing) led lights that was intended to be used in an outhouse.
With my zero knowledge of current and electrics I powered one of them into the newly bought 12V DC power (via M84 and Märklin 72090).
So if I got it right, a small led light which has a maximum of 25ma was powered into 500ma.
The rest is history...

What would be needed to buy in order to step down in power to be used for a led like this? https://modellbau-schoen...d-smd-3528-plcc2-kaltwei

I have a soldering iron but don't know if I need a switch regulator, resistor (I'm just name dropping stuff I've heard about).

Some LEDs are rated for about 1.5 V, some LEDs are rated around 3 V, some around 4 V.
Voltage is not the problem. Current is the problem because LEDs do not limit the current.

A resistor is the simple solution to limit the current to below 20 mA. Most LEDs can handle 20 mA, but make tests as some are very bright with 2 mA already.
A Google search for "led resistor calculator" finds many sites.

One of the easiest will be Farnell but I think for an outhouse you will fine that at 10mA the LED will be far too bright. My initial thought was to use a 10k ohm resistor, but as you won't be able to buy a single resistor (they will probably be a 5 or 10 pack minimum) you could purchase a smaller value like 2.2k and you can then use multiple resistors in series to achieve the desired brightness.

No, but I can't recall whether it's the anode or cathode you connect it to. There are plenty of diagrams on the Internet. The alternate method is to apply power to your resistor and apply that to one of your led connections with the power supply returnapplied to the other connection. If that doesn't work reverse the connections until it works. You won't damage the led as current will only flow one way.