The Märklin Einheitsmesswagen 49960 is equipped with a MM1 decoder. My Märklin Mobile Station 2 can't send MM1 signals. Therefore, the Messwagen isn't full useable and I was thinking about possibilities to replace the decoder:



Realization
The MM1 decoder chip is placed on the mainboard of the Messwagen. Furthermore, it is not possible to replace the decoder chip with another version. But I found a very good description here: http://donaupeter.de/moba/Messwagen/messwagen.htm

After I obtained this specific adapter board, I started to remove the unused parts, which is not so easy.

Here, You see in the upper window this adaptor board on the mainboard and on the second picture the decoder behind the mainboard:





Red-White headlights



The fiber optics leed to all three haedlights and are powered by one bulb:





To add red light to the lower headlights, only, I glued small red SMD-LEDs on the fiber optics edges:



The bulb was replaced by a single warm-white SMD-LED, placed on the same place like the bulb. And this is how it looks now:






Die Funktionen:

Geschwindigkeitsmessung

F1 = OFF
F2 = OFF
F3 = OFF
F4 = OFF

Messung in km/h (Vorbild)


F1 = OFF
F2 = OFF
F3 = ON
F4 = OFF

Messung in m/s (Modell)



Streckenmessung

F1 = ON
F2 = OFF
F3 = OFF
F4 = OFF

Maßeinheit km (Vorbild)


F1 = ON
F2 = OFF
F3 = ON
F4 = OFF

Maßeinheit m (Modell)


Zeit-Messung
F1 = OFF
F2 = ON
F3 = OFF
F4 = OFF

Maßeinheit Minuten (lang)


F1 = OFF
F2 = ON
F3 = OFF
F4 = OFF

Maßeinheit Sekunden (kurz)


Fahrzeit-Messung
F1 = ON
F2 = ON
F3 = OFF
F4 = OFF

Maßeinheit Stunden (Betriebsdauer)


F1 = ON
F2 = ON
F3 = ON
F4 = OFF

Maßeinheit Minuten (Fahrt)



And here without the case but in english:

Speed measure

F1 = OFF
F2 = OFF
F3 = OFF
F4 = OFF

Measure in km/h (Vorbild)


F1 = OFF
F2 = OFF
F3 = ON
F4 = OFF

Measure in m/s (Modell)


Distance Measure

F1 = ON
F2 = OFF
F3 = OFF
F4 = OFF

Measure in km (Vorbild)


F1 = ON
F2 = OFF
F3 = ON
F4 = OFF

Measure in m (Modell)


Time Measure
F1 = OFF
F2 = ON
F3 = OFF
F4 = OFF

Measure in Minutes (long)


F1 = OFF
F2 = ON
F3 = OFF
F4 = OFF

Measure in seconds (short)


Driving time measure
F1 = ON
F2 = ON
F3 = OFF
F4 = OFF

Measure in hours (total running time)


F1 = ON
F2 = ON
F3 = ON
F4 = OFF

Measure in minutes (single run)


F4 is to reset the measure values except the total running time.