I would like to show You my conversion of my lovely NS1202 (#3051): https://www.mittelleiter-magazin.de/umbauten/beleuchtungsplatine-fuer-maerklin-ns1202/
I created an LED light board to light the small back beams of this model:
The big lights remain white, the upper small ones to the left and right became red:
The circuit board fits into the case:
I sawed up the light guide body and glued in the corresponding light guide pins from the inside with some of the rest of the body. In this way, especially with headlights, the light is reliably guided into the light guide body and crosstalk from red to white or vice versa can be effectively prevented by appropriate separation.
But in meantime, I heard, that the light signal I created is wrong, isn't it?